Helm of the Host attached to Godo.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Godo with haste.
The token Godo enters the battlefield, causing you to search your library for an Equipment card and put it onto the battlefield.
Declare the token Godo as an attacker.
The token Godo triggers, untapping it and all Samurai you control and causing you to get an additional combat phase after this one.
Repeat each combat phase.

Helm attached to Aurelia.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Aurelia.
Declare the token Aurelia as an attacker.
The token Aurelia triggers, causing you to untap all creatures you control and get an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Combat Celebrant.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Combat Celebrant with haste.
Declare the token Combat Celebrant as an attacker choosing to exert it as it attacks.
The Combat Celebrant copy triggers, untapping all other creature you control and causing you to get an additional combat phase after this one.
Repeat.

Helm of the Host attached to Kiki-Jiki.

At the beginning of your combat phase, Helm of the Host triggers, creating a non-legendary copy of Kiki-Jiki.
Activate the untapped non-legendary Kiki-Jiki by tapping it, creating a token copy of itself.
Repeat step 2.

Helm of the Host attached to Port Razer.
An opponent is unable to block Port Razer.

At the beginning of combat, Helm of the Host triggers, creating a token copy of Port Razer with haste.
Declare the Port Razer token as an attacker.
When the Port Razer token deals combat damage, it triggers, causing you to untap all creatures you control and get another combat phase after this one.
Repeat.

Your life total is at most five.
You have the lowest life total or are tied for the lowest life total.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Scourge of the Throne with haste.
Declare the Scourge of the Throne token as an attacker, attacking the opponent with the most life or an opponent that is tied for the most life.
The Scourge of the Throne token's first and second abilities trigger.
Resolve the first trigger, giving the token +1/+1 until end of turn.
Resolve the second trigger, causing you to untap all attacking creatures and to get an additional combat phase after this one.
Repeat each combat phase.

You control another modified creature that can attack this turn, and that cannot be blocked and killed by an opponent.
Helm of the Host attached to Akki Battle Squad.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Akki Battle Squad with haste.
Declare another modified creature you control as an attacker.
Akki Battle Squad triggers, untapping all modified creatures you control and causing you to get an additional combat phase after this one.
Repeat each combat phase.

Breath of Fury attached to any other creature you control that can attack this turn and that cannot be blocked by an opponent.
Helm of the Host attached to any creature except the creature that has Breath of Fury attached.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of the creature it is attached to with haste.
Deal combat damage to an opponent using the creature that has Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to the token created in step 1, then causing you to untap all creatures you control and to get an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Dockside Extortionist.
Opponents control at least five artifacts and/or enchantments.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Dockside Extortionist with haste.
When the token Dockside Extortionist enters the battlefield, it triggers, creating at least five Treasure artifact tokens.
Move to your postcombat main phase.
Activate five Treasures by tapping and sacrificing them, adding .
Activate Aggravated Assault by paying , untapping all creatures you control and causing you to get an additional combat and main phase after this one.
Repeat.
If opponents control at least six artifacts and/or enchantments, this combo nets infinite Treasure tokens and colored mana.

Helm of the Host attached to Timestream Navigator.
You have the City's Blessing.

Go to combat, Helm of the Host triggers, creating a token copy of Timestream Navigator.
Activate the token copy of Timestream Navigator to take an extra turn.
Move to next turn.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Simic Growth Chamber.
Kodama of the East Tree, the Kodama of the East Tree token, and Simic Growth Chamber trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Simic Growth Chamber trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Simic Growth Chamber onto the battlefield.
The Kodama of the East Tree token and Simic Growth Chamber trigger.
Resolve the Simic Growth Chamber trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Simic Growth Chamber onto the battlefield.
Kodama of the East Tree and Simic Growth Chamber trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Simic Growth Chamber.
Both Kodama of the East Trees and Simic Growth Chamber trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Simic Growth Chamber trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Simic Growth Chamber from your hand onto the battlefield.
The token Kodama of the East Tree and Simic Growth Chamber trigger.
Resolve the Simic Growth Chamber trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Simic Growth Chamber from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Simic Growth Chamber trigger.
Repeat from step 5.

Helm of the Host attached to Faeburrow Elder.
Opponents can not block and kill creatures you control.
You control a blue and a black permanent.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Faeburrow Elder with haste.
Activate the Faeburrow Elder token by tapping it, adding .
Activate Najeela by paying , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Bloom Tender.
Opponents can not block and kill creatures you control.
You control a white, a blue, and a black permanent.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Bloom Tender with haste.
Activate the Bloom Tender token by tapping it, adding .
Activate Najeela by paying , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Gruul Turf.
Kodama of the East Tree, the Kodama of the East Tree token, and Gruul Turf trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Gruul Turf trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Gruul Turf onto the battlefield.
The Kodama of the East Tree token and Gruul Turf trigger.
Resolve the Gruul Turf trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Gruul Turf onto the battlefield.
Kodama of the East Tree and Gruul Turf trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Gruul Turf.
Both Kodama of the East Trees and Gruul Turf trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Gruul Turf trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Gruul Turf from your hand onto the battlefield.
The token Kodama of the East Tree and Gruul Turf trigger.
Resolve the Gruul Turf trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Gruul Turf from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Gruul Turf trigger.
Repeat from step 5.

Helm of the Host attached to Myr Galvanizer.
Myr Galvanizer and Palladium Myr do not have summoning sickness.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Myr Galvanizer with haste.
Activate Palladium Myr by tapping it, adding .
Activate a Myr Galvanizer by paying and tapping it, untapping all other Myr you control.
Repeat from step 2.

Helm of the Host attached to Ganax.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Ganax with haste.
The Ganax token enters the battlefield, triggering each Ganax you control, creating that many Treasure tokens.
Move to your postcombat main phase.
Activate all Treasure tokens you control by tapping and sacrificing them, adding at least .
Activate Aggravated Assault by paying , causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Helm of the Host attached to Dockside Extortionist.
Opponents control at least seven artifacts and/or enchantments.
An opponent cannot block and kill Hellkite Charger.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Dockside Extortionist with haste.
When the token Dockside Extortionist enters the battlefield, it triggers, creating at least seven Treasure artifact tokens.
Declare Hellkite Charger as an attacker, triggering its ability.
Holding priority, activate seven Treasures by tapping and sacrificing them, adding .
Resolve the Hellkite Charger trigger, causing you to pay to untap all attacking creatures you control and get an additional combat phase after this one.
Repeat each combat phase.
If opponents control at least eight artifacts and/or enchantments, this combo nets infinite Treasure tokens and colored mana.

Helm of the Host attached to Jegantha.
Opponents can not block and kill creatures you control.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Jegantha with haste that isn't legendary.
Activate the Jegantha token by tapping it, adding that cannot be spent to pay generic mana costs.
Activate Najeela by paying , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Selesnya Sanctuary.
Kodama of the East Tree, the Kodama of the East Tree token, and Selesnya Sanctuary trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Selesnya Sanctuary trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Selesnya Sanctuary onto the battlefield.
The Kodama of the East Tree token and Selesnya Sanctuary trigger.
Resolve the Selesnya Sanctuary trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Selesnya Sanctuary onto the battlefield.
Kodama of the East Tree and Selesnya Sanctuary trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Selesnya Sanctuary.
Both Kodama of the East Trees and Selesnya Sanctuary trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Selesnya Sanctuary trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Selesnya Sanctuary from your hand onto the battlefield.
The token Kodama of the East Tree and Selesnya Sanctuary trigger.
Resolve the Selesnya Sanctuary trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Selesnya Sanctuary from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Selesnya Sanctuary trigger.
Repeat from step 5.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Golgari Rot Farm.
Kodama of the East Tree, the Kodama of the East Tree token, and Golgari Rot Farm trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Golgari Rot Farm trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Golgari Rot Farm onto the battlefield.
The Kodama of the East Tree token and Golgari Rot Farm trigger.
Resolve the Golgari Rot Farm trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Golgari Rot Farm onto the battlefield.
Kodama of the East Tree and Golgari Rot Farm trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Golgari Rot Farm.
Both Kodama of the East Trees and Golgari Rot Farm trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Golgari Rot Farm trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Golgari Rot Farm from your hand onto the battlefield.
The token Kodama of the East Tree and Golgari Rot Farm trigger.
Resolve the Golgari Rot Farm trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Golgari Rot Farm from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Golgari Rot Farm trigger.
Repeat from step 5.

You have a way to put a +1/+1 counter on a colorless creature you control.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Omarthis with haste.
Put a +1/+1 counter on the Omarthis token or another colorless creature you control.
The nontoken Omarthis triggers, putting a +1/+1 counter on itself.
The Omarthis token triggers, putting a +1/+1 counter on itself.
Repeat from step 3.

Helm of the Host attached to Myr Battlesphere.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Myr Battlesphere with haste.
The Myr Battlesphere token enters the battlefield, creating four 1/1 Myr creature tokens.
Activate Time Sieve by tapping it, sacrificing the Myr Battlesphere token and sacrificing the four Myr tokens, causing you to take an extra turn after this one.
Repeat each turn.

Helm of the Host attached to Azor.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Azor with haste.
The Azor token enters the battlefield, preventing opponents from casting instants or sorceries during their next turn.
Repeat each turn.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Guildless Commons.
Kodama of the East Tree, the Kodama of the East Tree token, and Guildless Commons trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Guildless Commons trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Guildless Commons onto the battlefield.
The Kodama of the East Tree token and Guildless Commons trigger.
Resolve the Guildless Commons trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Guildless Commons onto the battlefield.
Kodama of the East Tree and Guildless Commons trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Guildless Commons.
Both Kodama of the East Trees and Guildless Commons trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Guildless Commons trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Guildless Commons from your hand onto the battlefield.
The token Kodama of the East Tree and Guildless Commons trigger.
Resolve the Guildless Commons trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Guildless Commons from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Guildless Commons trigger.
Repeat from step 5.

Helm of the Host attached to Biovisionary.
You control at least one additional token.

At the beginning of your combat phase, Helm of the Host and Brudiclad trigger.
Resolve the Helm of the Host trigger, creating a token copy of Biovisionary with haste.
Resolve the Brudiclad trigger, creating a 2/1 Phyrexian Myr creature token, then choosing to have all tokens you control become copies of the Biovisionary token.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first Biovisionary trigger, causing you to win the game.

Helm of the Host attached to Academy Manufactor.
You control at least five additional artifacts.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Academy Manufactor with haste.
Activate Time Sieve by tapping it and sacrificing five artifacts, causing you to take an extra turn after this one.
Move to your next turn.
At the beginning of your upkeep, Tamiyo's Journal triggers, creating three Food, three Clue, and three Treasure artifact tokens.
Repeat from step 2.

Helm of the Host attached to Kodama of the East Tree.
An additional nonartifact permanent card in your hand that you are able to play.
An additional nonartifact permanent card on the battlefield that shares a type with the card in your hand and that has an equal or lesser mana cost.

At the beginning of combat, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree.
When the token enters the battlefield, Cloudstone Curio and the original Kodama of the East Tree trigger; decline to use these abilities unless desired.
In your second main phase, play the nonartifact permanent in your hand.
When it enters the battlefield, Cloudstone Curio and both copies of Kodama of the East Tree trigger.
Resolve the Cloudstone Curio trigger, returning the other nonartifact permanent from the battlefield to your hand.
Resolve the first Kodama of the East Tree trigger, putting the permanent you returned in step 5 from your hand onto the battlefield.
When that permanent enters the battlefield, Cloudstone Curio and the second Kodama of the East Tree trigger.
Resolve the Cloudstone Curio trigger, returning the permanent you played in step 3 from the battlefield to your hand.
Resolve the Kodama of the East Tree trigger from step 7, declining to use it unless desired.
Resolve the remaining Kodama of the East Tree trigger from step 4, putting the permanent you returned in step 8 from your hand onto the battlefield.
Repeat from step 4 any number of times.
This combo results in Infinite ETB and Infinite LTB if a permanent involved is a creature, and/or Infinite landfall triggers if it is a land.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Dimir Aqueduct.
Kodama of the East Tree, the Kodama of the East Tree token, and Dimir Aqueduct trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Dimir Aqueduct trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Dimir Aqueduct onto the battlefield.
The Kodama of the East Tree token and Dimir Aqueduct trigger.
Resolve the Dimir Aqueduct trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Dimir Aqueduct onto the battlefield.
Kodama of the East Tree and Dimir Aqueduct trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Dimir Aqueduct.
Both Kodama of the East Trees and Dimir Aqueduct trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Dimir Aqueduct trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Dimir Aqueduct from your hand onto the battlefield.
The token Kodama of the East Tree and Dimir Aqueduct trigger.
Resolve the Dimir Aqueduct trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Dimir Aqueduct from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Dimir Aqueduct trigger.
Repeat from step 5.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Boros Garrison.
Kodama of the East Tree, the Kodama of the East Tree token, and Boros Garrison trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Boros Garrison trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Boros Garrison onto the battlefield.
The Kodama of the East Tree token and Boros Garrison trigger.
Resolve the Boros Garrison trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Boros Garrison onto the battlefield.
Kodama of the East Tree and Boros Garrison trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Boros Garrison.
Both Kodama of the East Trees and Boros Garrison trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Boros Garrison trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Boros Garrison from your hand onto the battlefield.
The token Kodama of the East Tree and Boros Garrison trigger.
Resolve the Boros Garrison trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Boros Garrison from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Boros Garrison trigger.
Repeat from step 5.

You have a way to put a +1/+1 counter on Enduring Scalelord.
Helm of the Host attached to Enduring Scalelord.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Enduring Scalelord with haste.
Put a +1/+1 counter on either Enduring Scalelord.
The Enduring Scalelord who didn't have the counter put on it triggers, putting a +1/+1 counter on itself.
Repeat step 3.

Helm of the Host attached to Coretapper.

At the beginning of combat on your turn, Helm of the Host triggers, creating a token copy of Coretapper with haste.
Activate the token Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter.
Activate the token Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, causing you to take an extra turn after this one.
Repeat each turn.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Izzet Boilerworks.
Kodama of the East Tree, the Kodama of the East Tree token, and Izzet Boilerworks trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Izzet Boilerworks trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Izzet Boilerworks onto the battlefield.
The Kodama of the East Tree token and Izzet Boilerworks trigger.
Resolve the Izzet Boilerworks trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Izzet Boilerworks onto the battlefield.
Kodama of the East Tree and Izzet Boilerworks trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Izzet Boilerworks.
Both Kodama of the East Trees and Izzet Boilerworks trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Izzet Boilerworks trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Izzet Boilerworks from your hand onto the battlefield.
The token Kodama of the East Tree and Izzet Boilerworks trigger.
Resolve the Izzet Boilerworks trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Izzet Boilerworks from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Izzet Boilerworks trigger.
Repeat from step 5.

Helm of the Host attached to Dockside Extortionist.
Opponents control at least five artifacts and/or enchantments.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Dockside Extortionist with haste.
When the token Dockside Extortionist enters the battlefield, it triggers, creating at least five Treasure artifact tokens.
Activate five Treasures by tapping and sacrificing them, adding .
Activate Najeela by paying , untapping all attacking creatures, giving them trample, lifelink and haste, and gaining an additional combat phase after this one.
Repeat each combat phase.
If opponents control at least six artifacts and/or enchantments, this combo nets infinite Treasure tokens and colored mana.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Azorius Chancery.
Kodama of the East Tree, the Kodama of the East Tree token, and Azorius Chancery trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Azorius Chancery trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Azorius Chancery onto the battlefield.
The Kodama of the East Tree token and Azorius Chancery trigger.
Resolve the Azorius Chancery trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Azorius Chancery onto the battlefield.
Kodama of the East Tree and Azorius Chancery trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Azorius Chancery.
Both Kodama of the East Trees and Azorius Chancery trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Azorius Chancery trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Azorius Chancery from your hand onto the battlefield.
The token Kodama of the East Tree and Azorius Chancery trigger.
Resolve the Azorius Chancery trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Azorius Chancery from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Azorius Chancery trigger.
Repeat from step 5.

Helm of the Host attached to Sage of Hours.
Master Biomancer has power five or greater.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Sage of Hours with haste that enters the battlefield with at least five +1/+1 counters on it due to Master Biomancer.
Activate the Sage of Hours copy by removing all +1/+1 counters from it, causing you to take at least one extra turn after this one.
Repeat.

You have a way to put a +1/+1 counter on a colorless creature you control.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Omarthis with haste.
Put a +1/+1 counter on the Omarthis token or another colorless creature you control.
The nontoken Omarthis triggers, putting a +1/+1 counter on itself.
The Omarthis token triggers, putting a +1/+1 counter on itself.
Repeat from step 3.

Helm of the Host attached to Identity Thief.
Identity Thief does not have summoning sickness.
Opponents can not block Medomai token.

Move to combat.
Helm of the Host will trigger and create a copy of Identity Thief.
Attack with the Identity Thief token, triggering it and exiling Medomai the Ageless until end of turn.
the Identity Thief token will deal combat damage as a copy of Medomai the Ageless, granting you an extra turn.
At the end of the turn, Medomai the Ageless returns to the battlefield.
Sacrifice the token.
Repeat for infinite turns.

Helm of the Host attached to Éomer.
Kari Zev does not have summoning sickness and cannot be blocked and killed by an opponent.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Kari Zev as an attacker.
Kari Zev triggers, creating a legendary 2/1 Ragavan creature token that is tapped and attacking.
Holding priority, activate Goblin Bombardment by sacrificing Ragavan.
When Ragavan dies, each Éomer that hasn't triggered this turn triggers, untapping all creatures you control and causing you to get at least one additional combat phase after this one.
Resolve the Goblin Bombardment ability, dealing 1 damage to any target.
Repeat each combat phase.

Helm of the Host attached to Biovisionary.

At the beginning of your combat phase, Helm of the Host triggers.
Holding priority, activate Lithoform Engine's first ability by paying and tapping it, copying Helm of the Host's trigger.
Activate Strionic Resonator by paying and tapping it, copying Helm of the Host's trigger.
Resolve all Helm of the Host triggers, creating three token copies of Biovisionary with haste.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first trigger, causing you to win the game.

Helm of the Host attached to Éomer.
Kari Zev does not have summoning sickness and cannot be blocked and killed by an opponent.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Kari Zev as an attacker.
Kari Zev triggers, creating a legendary 2/1 Ragavan creature token that is tapped and attacking.
Holding priority, activate Ashnod's Altar by sacrificing Ragavan, adding .
When Ragavan dies, each Éomer that hasn't triggered this turn triggers, untapping all creatures you control and causing you to get at least one additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Orzhov Basilica.
Kodama of the East Tree, the Kodama of the East Tree token, and Orzhov Basilica trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Orzhov Basilica trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Orzhov Basilica onto the battlefield.
The Kodama of the East Tree token and Orzhov Basilica trigger.
Resolve the Orzhov Basilica trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Orzhov Basilica onto the battlefield.
Kodama of the East Tree and Orzhov Basilica trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Orzhov Basilica.
Both Kodama of the East Trees and Orzhov Basilica trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Orzhov Basilica trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Orzhov Basilica from your hand onto the battlefield.
The token Kodama of the East Tree and Orzhov Basilica trigger.
Resolve the Orzhov Basilica trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Orzhov Basilica from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Orzhov Basilica trigger.
Repeat from step 5.

Helm of the Host attached to Kodama of the East Tree.
Helm of the Host attached to Kodama of the East Tree.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Kodama of the East Tree that isn't legendary.
Play Rakdos Carnarium.
Kodama of the East Tree, the Kodama of the East Tree token, and Rakdos Carnarium trigger.
Resolve the Kodama of the East Tree token's trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Rakdos Carnarium trigger, returning it to your hand.
Resolve the Kodama of the East Tree trigger, putting Rakdos Carnarium onto the battlefield.
The Kodama of the East Tree token and Rakdos Carnarium trigger.
Resolve the Rakdos Carnarium trigger, returning it to your hand.
Resolve the Kodama of the East Tree token's trigger, putting Rakdos Carnarium onto the battlefield.
Kodama of the East Tree and Rakdos Carnarium trigger.
Repeat from step 5.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Kodama of the East Tree with haste.
Play Rakdos Carnarium.
Both Kodama of the East Trees and Rakdos Carnarium trigger.
Resolve the token Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Rakdos Carnarium trigger, returning it to your hand from the battlefield.
Resolve the nontoken Kodama of the East Tree trigger, putting Rakdos Carnarium from your hand onto the battlefield.
The token Kodama of the East Tree and Rakdos Carnarium trigger.
Resolve the Rakdos Carnarium trigger, returning it to your hand from the battlefield.
Resolve the token Kodama of the East Tree trigger, putting Rakdos Carnarium from your hand onto the battlefield.
The nontoken Kodama of the East Tree and Rakdos Carnarium trigger.
Repeat from step 5.

You have a way to put a +1/+1 counter on a colorless creature you control.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Omarthis with haste.
Put a +1/+1 counter on the Omarthis token or another colorless creature you control.
The nontoken Omarthis triggers, putting a +1/+1 counter on itself.
The Omarthis token triggers, putting a +1/+1 counter on itself.
Repeat from step 3.

Helm of the Host attached to Éomer.
Stangg does not have summoning sickness.
An opponent cannot block and kill Stangg.
You control another legendary creature that can attack this turn.
You have a way to kill the additional legendary creature at instant speed.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Stangg and the additional legendary creature as attackers.
Stangg triggers, creating a 3/4 Stangg Twin creature token that is tapped and attacking.
Holding priority, kill the additional legendary creature.
When the creature dies, each Éomer that has not triggered this turn triggers, causing you to untap all creatures you control and to get at least one additional combat phase after this one.
Move to your next combat phase.
At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Stangg as an attacker.
Stangg triggers, creating a 3/4 Stangg Twin creature token that is tapped and attacking.
Put either Stangg Twin token into your graveyard due to the legend rule.
Repeat from step 5.

Helm of the Host attached to Composite Golem.

At the beginning of combat during your turn, Helm of the Host triggers, creating a token copy of Composite Golem.
Activate the Composite Golem token by sacrificing it, adding .
Activate Najeela by paying , untapping all attacking creatures, giving them trample, lifelink and haste, and getting an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Éomer.
Kari Zev does not have summoning sickness and cannot be blocked and killed by an opponent.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Kari Zev as an attacker.
Kari Zev triggers, creating a legendary 2/1 Ragavan creature token that is tapped and attacking.
Holding priority, activate Phyrexian Altar by sacrificing Ragavan, adding .
When Ragavan dies, each Éomer that hasn't triggered this turn triggers, untapping all creatures you control and causing you to get at least one additional combat phase after this one.
Repeat each combat phase.

You control at least one Clue token.
Helm of the Host attached to Lonis.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Lonis.
Activate Krark-Clan Ironworks by sacrificing a Clue, adding .
Lonis and the Lonis token's second abilities trigger.
Resolve the nontoken Lonis trigger, putting a +1/+1 counter on the token Lonis.
The token Lonis's first ability triggers, creating a Clue artifact token.
Resolve the token Lonis's trigger from step 2, putting a +1/+1 counter on the nontoken Lonis.
The nontoken Lonis's first ability triggers, creating a Clue artifact token.
Repeat from step 2.

You may optionally target any other creature using one of the triggers to put infinite +1/+1 counters on that creature.
Once you have infinite mana, you may instead sacrifice the Clues to their own abilities

Helm of the Host attached to Kodama.
You have not completed Tomb of Annihilation.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary copy of Kodama.
Cast Acererak by paying .
Acererak enters the battlefield, triggering itself, Kodama and the Kodama token.
Resolve the nontoken Kodama trigger, choosing not to put anything on the battlefield.
Resolve the Acererak trigger, returning it from the battlefield to your hand and venturing into any dungeon except Tomb of Annihilation.
Resolve the token Kodama trigger, putting Acererak from your hand onto the battlefield.
Acererak enters the battlefield, triggering itself and the nontoken Kodama.
Resolve the Acererak trigger, returning it from the battlefield to your hand and venturing into any dungeon except Tomb of Annihilation.
Resolve the nontoken Kodama trigger, putting Acererak from your hand onto the battlefield.
Acererak enters the battlefield, triggering itself and the token Kodama.
Repeat from step 5.

Helm of the Host attached to Éomer.
Kari Zev does not have summoning sickness and cannot be blocked and killed by an opponent.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Kari Zev as an attacker.
Kari Zev triggers, creating a legendary 2/1 Ragavan creature token that is tapped and attacking.
Holding priority, activate Altar of Dementia by sacrificing Ragavan.
When Ragavan dies, each Éomer that hasn't triggered this turn triggers, untapping all creatures you control and causing you to get at least one additional combat phase after this one.
Resolve the Altar of Dementia ability, causing target player to mill cards equal to Ragavan's power.
Repeat each combat phase.

Helm of the Host attached to Aberrant Mind Sorcerer.

Cast Time Warp by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Aberrant Mind Sorcerer with haste.
When the Aberrant Mind Sorcerer token enters the battlefield, it triggers, causing you to roll a d20 and either return Time Warp from your graveyard to your hand, or put Time Warp from your graveyard on top of your library.
Move to your extra turn, drawing Time Warp if it was put on top of your library.
Repeat.

Helm of the Host attached to Kurkesh.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary copy of Kurkesh with haste.
Activate Gilded Lotus by tapping it, adding .
Activate Clock of Omens by tapping itself and Helm of the Host, targeting Gilded Lotus.
Both Kurkeshes trigger.
Resolve both Kurkesh triggers, causing you to pay to copy Clock of Omens' ability twice, targeting Clock of Omens and Helm of the Host.
Resolve all Clock of Omens abilties, untapping it, Helm of the Host and Gilded Lotus.
Repeat from step 3.

You control at least one Clue token.
Helm of the Host attached to Lonis.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Lonis.
Activate Grinding Station by tapping it and sacrificing a Clue.
Lonis and the Lonis token's second abilities trigger.
Resolve the nontoken Lonis trigger, putting a +1/+1 counter on the token Lonis.
The token Lonis's first ability triggers, creating a Clue artifact token.
When the Clue enters the battlefield, Grinding Station triggers, untapping Grinding Station.
Resolve the token Lonis's trigger from step 2, putting a +1/+1 counter on the nontoken Lonis.
The nontoken Lonis's first ability triggers, creating a Clue artifact token.
When the Clue enters the battlefield, Grinding Station triggers, untapping Grinding Station.
Resolve the Grinding Station ability.
Repeat from step 2.

You may optionally target any other creature using one of the triggers to put infinite +1/+1 counters on that creature.

You control at least one Clue token.
Helm of the Host attached to Lonis.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Lonis.
Activate Arcbound Ravager by sacrificing a Clue.
Lonis and the Lonis token's second abilities trigger.
Resolve the nontoken Lonis trigger, putting a +1/+1 counter on the token Lonis.
The token Lonis's first ability triggers, creating a Clue artifact token.
Resolve the token Lonis's trigger from step 2, putting a +1/+1 counter on the nontoken Lonis.
The nontoken Lonis's first ability triggers, creating a Clue artifact token.
Resolve the Arcbound Ravager ability.
Repeat from step 2.

You may optionally target any other creature using one of the triggers to put infinite +1/+1 counters on that creature.

You have a way to put a +1/+1 counter on a colorless creature you control.
"Spirit" or "Naga" chosen with Vanquisher's Banner.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Omarthis with haste.
Put a +1/+1 counter on the Omarthis token or another colorless creature you control.
The nontoken Omarthis triggers, putting a +1/+1 counter on itself.
The Omarthis token triggers, putting a +1/+1 counter on itself.
Repeat from step 3.

Helm of the Host attached to Felidar Guardian.
You control at least one nontoken creature with base power 4 or greater.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Felidar Guardian with haste.
When the Felidar Guardian token enters the battlefield, it triggers, blinking any creature you control with base power 4 or greater.
When the creature enters the battlefield, Life Finds A Way triggers, creating a token copy of the Felidar Guardian token.
Repeat from step 2.

You have a way to put a +1/+1 counter on a colorless creature you control.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Omarthis with haste.
Put a +1/+1 counter on the Omarthis token or another colorless creature you control.
The nontoken Omarthis triggers, putting a +1/+1 counter on itself.
The Omarthis token triggers, putting a +1/+1 counter on itself.
Repeat from step 3.

Helm of the Host attached to Aberrant Mind Sorcerer.

Cast Temporal Manipulation by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Aberrant Mind Sorcerer with haste.
When the Aberrant Mind Sorcerer token enters the battlefield, it triggers, causing you to roll a d20 and either return Temporal Manipulation from your graveyard to your hand, or put Temporal Manipulation from your graveyard on top of your library.
Move to your extra turn, drawing Temporal Manipulation if it was put on top of your library.
Repeat.

Helm of the Host attached to Aberrant Mind Sorcerer.

Cast Time Stretch by paying , causing you to take two extra turns after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Aberrant Mind Sorcerer with haste.
When the Aberrant Mind Sorcerer token enters the battlefield, it triggers, causing you to roll a d20 and either return Time Stretch from your graveyard to your hand, or put Time Stretch from your graveyard on top of your library.
Move to your first extra turn, drawing Time Stretch if it was put on top of your library.
Move to your second extra turn.
Repeat.

Helm of the Host attached to Aberrant Mind Sorcerer.

Cast Capture of Jingzhou by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Aberrant Mind Sorcerer with haste.
When the Aberrant Mind Sorcerer token enters the battlefield, it triggers, causing you to roll a d20 and either return Capture of Jingzhou from your graveyard to your hand, or put Capture of Jingzhou from your graveyard on top of your library.
Move to your extra turn, drawing Capture of Jingzhou if it was put on top of your library.
Repeat.

Helm of the Host attached to Sage of Hours.
Bloodspore Thrinax has at least five +1/+1 counters on it.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Sage of Hours with haste that enters the battlefield with at least five +1/+1 counters on it due to Bloodspore Thrinax.
Activate the Sage of Hours copy by removing all +1/+1 counters from it, causing you to take at least one extra turn after this one.
Repeat.

Sage of Hours does not have summoning sickness and cannot be blocked by an opponent.
Helm of the Host attached to Conclave Sledge-Captain.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Conclave Sledge-Captain with haste.
When the Conclave Sledge-Captain token enters the battlefield, its backup ability triggers three times, all targeting Sage of Hours.
Resolve all Conclave Sledge-Captain triggers, putting three +1/+1 counters on Sage of Hours, and causing it to gain the printed abilities three times until end of turn.
Deal combat damage with Sage of Hours, triggering its abilities granted by Conclave Sledge-Captain three times, putting three +1/+1 counters on Sage of Hours for each damage it dealt.
Activate Sage of Hours by removing all +1/+1 counters from it, causing you to take at least three extra turns after this one.
Repeat during your last extra turn.

Helm of the Host attached to Sidisi.

At the beginning of combat on your turn, Helm of the Host triggers, creating a non-legendary copy of Sidisi with haste.
The non-legendary Sidisi enters the battlefield, triggering its exploit ability, sacrificing itself.
Sidisi's second ability triggers, allowing you to search your library for Nexus of Fate, put it into your hand, and shuffle your library.
Cast Nexus of Fate by paying , causing you to take an extra turn after this one and shuffle it into your library.
Repeat.

Helm of the Host attached to Restoration Angel.
You control at least one nontoken non-Angel creature with base power 4 or greater.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Restoration Angel with haste.
When the Restoration Angel token enters the battlefield, it triggers, blinking any non-Angel you control with base power 4 or greater.
When the creature enters the battlefield, Life Finds A Way triggers, creating a token copy of the Restoration Angel token.
Repeat from step 2.

Helm of the Host attached to Sidisi.

At the beginning of combat on your turn, Helm of the Host triggers, creating a non-legendary copy of Sidisi with haste.
The non-legendary Sidisi enters the battlefield, triggering its exploit ability, sacrificing itself.
Sidisi's second ability triggers, causing you to search your library for Beacon of Tomorrows, put it into your hand, and shuffle your library.
Cast Beacon of Tomorrows by paying , causing you to take an extra turn after this one and shuffle it into your library.
Repeat.

Helm of the Host attached to Aberrant Mind Sorcerer.

Cast Walk the Aeons by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Aberrant Mind Sorcerer with haste.
When the Aberrant Mind Sorcerer token enters the battlefield, it triggers, causing you to roll a d20 and either return Walk the Aeons from your graveyard to your hand, or put Walk the Aeons from your graveyard on top of your library.
Move to your extra turn, drawing Walk the Aeons if it was put on top of your library.
Repeat.

Helm of the Host attached to Izzet Chemister.

Cast Time Warp by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Time Warp from your graveyard.
On your next turn, activate the Izzet Chemister token's last ability by paying , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost.
Resolve that spell, causing you to take an extra turn after this one.
Repeat from step 2.

Helm of the Host attached to Biovisionary.
The Peregrine Dynamo does not have summoning sickness.

At the beginning of your combat phase, Helm of the Host triggers.
Holding priority, activate Strionic Resonator by paying and tapping it, copying Helm of the Host's trigger.
Activate The Peregrine Dynamo by paying and tapping it, copying Helm of the Host's trigger.
Resolve all Helm of the Host triggers, creating three token copies of Biovisionary with haste.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first trigger, causing you to win the game.

Helm of the Host attached to Biovisionary.
The Peregrine Dynamo does not have summoning sickness.

At the beginning of your combat phase, Helm of the Host triggers.
Holding priority, activate Lithoform Engine's first ability by paying and tapping it, copying Helm of the Host's trigger.
Activate The Peregrine Dynamo by paying and tapping it, copying Helm of the Host's trigger.
Resolve all Helm of the Host triggers, creating three token copies of Biovisionary with haste.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first trigger, causing you to win the game.

Helm of the Host attached to Biovisionary.
Abstruse Archaic and The Peregrine Dynamo do not have summoning sickness.

At the beginning of your combat phase, Helm of the Host triggers.
Holding priority, activate The Peregrine Dynamo by paying and tapping it, copying Helm of the Host's trigger.
Activate Abstruse Archaic by paying and tapping it, copying Helm of the Host's trigger.
Resolve all Helm of the Host triggers, creating three token copies of Biovisionary with haste.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first trigger, causing you to win the game.

Helm of the Host attached to Biovisionary.
Abstruse Archaic does not have summoning sickness.

At the beginning of your combat phase, Helm of the Host triggers.
Holding priority, activate Strionic Resonator by paying and tapping it, copying Helm of the Host's trigger.
Activate Abstruse Archaic by paying and tapping it, copying Helm of the Host's trigger.
Resolve all Helm of the Host triggers, creating three token copies of Biovisionary with haste.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first trigger, causing you to win the game.

Helm of the Host attached to Biovisionary.
Abstruse Archaic does not have summoning sickness.

At the beginning of your combat phase, Helm of the Host triggers.
Holding priority, activate Lithoform Engine's first ability by paying and tapping it, copying Helm of the Host's trigger.
Activate Abstruse Archaic by paying and tapping it, copying Helm of the Host's trigger.
Resolve all Helm of the Host triggers, creating three token copies of Biovisionary with haste.
At the beginning of your end step, each Biovisionary triggers.
Resolve the first trigger, causing you to win the game.

Helm of the Host attached to Academy Manufactor.
Hoard Robber does not have summoning sickness and cannot be blocked by at least one opponent.

At the beginning of your combat step, Helm of the Host triggers, creating a token copy of Academy Manufactor.
Attack with Hoard Robber.
Hoard Robber triggers on combat damage to a player, creating three Treasure tokens, three Food tokens, and three Clue tokens.
Activate Time Sieve's ability by tapping Time Sieve and sacrificing five artifacts you control, taking an extra turn after this one.
Repeat.

Helm of the Host attached to Najeela.
Najeela does not have summoning sickness.
An opponent cannot block and kill enough of your creatures to end the combo.

At the beginning of combat, Helm of the Host and Brudiclad trigger.
Resolve Helm of the Host's trigger, creating a nonlegendary copy of Najeela with haste.
Resolve Brudiclad's trigger, creating a token, then causing all tokens you control to become copies of the nonlegendary Najeela token with haste.
Attack with at least three Najeela creatures.
Each Najeela triggers at least three times each, creating a total of at least nine Warrior tokens that are tapped and attacking.
Activate Phyrexian Altar at least five times by sacrificing at least five Warrior tokens, adding at least .
Pay to activate any Najeela, untapping all attacking creatures, giving them trample, lifelink, and haste until end of turn, and creating an additional combat phase after this one.
Deal combat damage, gaining life equal to the amount of damage dealt.
Repeat.

You have a way to put a +1/+1 counter on a colorless creature you control.
"Spirit" or "Naga" chosen with Instruments of War.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Omarthis with haste.
Put a +1/+1 counter on the Omarthis token or another colorless creature you control.
The nontoken Omarthis triggers, putting a +1/+1 counter on itself.
The Omarthis token triggers, putting a +1/+1 counter on itself.
Repeat from step 3.

Helm of the Host attached to Izzet Chemister.

Cast Time Stretch by paying , causing you to take two extra turns after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Time Stretch from your graveyard.
On your next turn, activate the Izzet Chemister token's last ability by paying , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost.
Resolve that spell, causing you to take two extra turns after this one.
Repeat from step 2 (note that you may divide these steps among your multiple extra turns to reduce the mana requirements down to the amount shown in the prerequisites).

Helm of the Host and Mirror Mockery attached to Roalesk.
One opponent can be attacked.

At the beginning of combat, Helm of the Host will trigger, making a nonlegendary copy of Roalesk.
When the Roalesk token ETBs, put the 2 +1/+1 counters on Sage of Hours.
Attack with the nontoken Roalesk.
Mirror Mockery triggers, making a copy of Roalesk.
Place its ETB trigger onto the stack targeting Sage of hours, then sacrifice this token copy due to the legend rule, proliferating the +1/+1 counters on Sage of Hours up to 4.
Resolve the ETB trigger, increasing the total number of +1/+1 counters on Sage of Hours to 6.
Remove all +1/+1 counters from Sage of Hours to take an extra turn.
Repeat for infinite turns.

Helm of the Host attached to Éomer.
Kari Zev does not have summoning sickness and cannot be blocked and killed by an opponent.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Éomer with haste.
Declare Kari Zev as an attacker.
Kari Zev triggers, creating a legendary 2/1 Ragavan creature token that is tapped and attacking.
Holding priority, activate Thermopod's second ability by sacrificing Ragavan, adding .
When Ragavan dies, each Éomer that hasn't triggered this turn triggers, untapping all creatures you control and causing you to get at least one additional combat phase after this one.
Repeat each combat phase.

An opponent cannot block and kill Hellkite Charger or Fire Lord Ozai

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of the creature it is attached to.
Declare Hellkite Charger and Fire Lord Ozai as attackers, triggering their abilities.
Resolve the Fire Lord Ozai trigger, causing you to sacrifice the token made in step 1 and add an amount of equal to the token's power.
Resolve the Hellkite Charger trigger, causing you to pay to untap all attacking creatures and to get an additional combat phase after this one.
Repeat each combat phase.

Helm of the Host attached to Izzet Chemister.

Cast Capture of Jingzhou by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Capture of Jingzhou from your graveyard.
On your next turn, activate the Izzet Chemister token's last ability by paying , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost.
Resolve that spell, causing you to take an extra turn after this one.
Repeat from step 2.

Helm of the Host attached to Izzet Chemister.

Cast Walk the Aeons by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Walk the Aeons from your graveyard.
On your next turn, activate the Izzet Chemister token's last ability by paying , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost.
Resolve that spell, causing you to take an extra turn after this one.
Repeat from step 2.

Helm of the Host attached to Izzet Chemister.

Cast Temporal Manipulation by paying , causing you to take an extra turn after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Temporal Manipulation from your graveyard.
On your next turn, activate the Izzet Chemister token's last ability by paying , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost.
Resolve that spell, causing you to take an extra turn after this one.
Repeat from step 2.

Helm of the Host attached to Avenger of Zendikar.
You control at least four lands.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Avenger of Zendikar with haste.
When the Avenger of Zendikar token enters the battlefield, it triggers, creating a 0/1 Plant creature token for each land you control.
Activate Time Sieve by tapping it and sacrificing five creature tokens, causing you to take an extra turn after this one.
Repeat each turn.

Helm of the Host attached to Lena.
You control at least four nontoken creatures.

At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Lena with haste.
The Lena token triggers, creating a number of 1/1 Soldier creature tokens equal to the number of nontoken creatures you control.
Activate Time Sieve by tapping it and sacrificing five creature tokens, causing you to take an extra turn after this one.
Repeat each turn.

Helm of the Host attached to Avenger of Zendikar.
You control at least four lands.

At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Avenger of Zendikar with haste.
The Avenger of Zendikar token enters the battlefield, creating a 0/1 Plant creature token for each land you control.
Activate Time Sieve by tapping it and sacrificing five creature tokens, causing you to take an extra turn after this one.
Repeat each turn.