Walking Ballista has at least two +1/+1 counters on it.

Activate Heliod by paying , giving Walking Ballista lifelink until end of turn.
Activate Walking Ballista's second ability by removing a +1/+1 counter, dealing 1 damage to any target.
Walking Ballista's lifelink triggers, causing you to gain 1 life.
Heliod triggers, putting a +1/+! counter on Walking Ballista.
Repeat from step 2.

Your life total is at least 2.
You control at least one additional nontoken non-Human creature with toughness two or greater.

Activate Yawgmoth by paying 1 life and sacrificing Gray Merchant, targeting any other nontoken non-Human creature you control.
Gray Merchant dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Gray Merchant enters the battlefield, causing each opponent to lose life equal to your devotion to black, and causing you to gain life equal to the life lost this way.
Resolve the Yawgmoth ability from step 1, putting a -1/-1 counter on the additional creature and causing you to draw a card.
Activate Yawgmoth by paying 1 life and sacrificing the additional creature, targeting Gray Merchant.
The creature dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the Yawgmoth ability, putting a -1/-1 counter on Gray Merchant and causing you to draw a card.
Repeat.

Your life total is at least 2.
You have at least three devotion to blue.

Cast Doomsday by paying , searching your library and graveyard for any five other cards, exiling all other cards from your graveyard and library, and then placing the remaining cards on top of your library and losing half your life, rounded up.
Cast Thassa's Oracle by paying .
Thassa's Oracle enters the battlefield, winning the game.

Triskelion has at least two +1/+1 counters on it.

If Triskelion has at least three +1/+1 counters on it, activate Triskelion by removing a +1/+1 counter from it, dealing 1 damage to any target.
Repeat step 1 until there are two +1/+1 counters remaining on Triskelion.
Activate Triskelion by removing a +1/+1 counter from Triskelion, dealing 1 damage to itself.
Repeat step 3 an additional time.
Triskelion dies.
Triskelion's undying ability triggers, returning it to the battlefield with an additional +1/+1 counter on it.
Repeat.

Your life total is at least 2.
You control at least one additional nontoken non-Human creature with toughness two or greater.

Activate Yawgmoth by paying 1 life and sacrificing Ayara, targeting any other nontoken non-Human creature you control.
Ayara dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Ayara enters the battlefield, causing each opponent to lose 1 life and you to gain 1 life.
Resolve the Yawgmoth ability from step 1, putting a -1/-1 counter on the additional creature and causing you to draw a card.
Activate Yawgmoth by paying 1 life and sacrificing the additional creature, targeting Ayara.
The creature dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
If the creature was black, it enters the battlefield, triggering Ayara, causing each opponent to lose 1 life and you to gain 1 life.
Resolve the Yawgmoth ability, putting a -1/-1 counter on Ayara and causing you to draw a card.
Repeat.

Activate Heliod targeting Triskelion, giving it lifelink until end of turn.
Activate Triskelion by removing a +1/+1 counter from it to deal 1 damage to any target, gaining you 1 life.
Heliod triggers, putting a +1/+1 counter on Triskelion.
Repeat from step 2 for infinite damage and lifegain.

Emry does not have summoning sickness.

Activate Mindslaver by paying , tapping and sacrificing it, gaining control of target player's next turn.
Activate Emry by tapping it, allowing you to cast Mindslaver from your graveyard this turn.
Cast Mindslaver from your graveyard by paying .
Pass the turn.
End the controlled opponent turn.
Repeat.

Cast Basalt Monolith by paying .
Displacer Kitten triggers, blinking Teferi.
Activate Basalt Monolith's first ability by tapping it, adding .
Activate Teferi's second loyalty ability by removing three loyalty counters from it, returning Basalt Monolith from the battlefield to your hand and drawing a card.
Repeat.

You control at least six Islands.

Cast High Tide for .
Cast Palinchron for .
Palinchron enters the battlefield, untapping at least six Islands you control.
Activate six Islands you control by tapping them, adding twelve .
Activate Palinchron by paying , returning Palinchron to your hand.
Repeat from step 2.

You have not cast a spell using Lurrus this turn.

Activate Lotus Petal by tapping and sacrificing it, adding one mana of any color.
Cast Lotus Petal from your graveyard by paying .
Displacer Kitten triggers, blinking Lurrus.
Repeat.

You control up to seven lands that can tap to produce at least .

Activate up to seven lands you control by tapping them, adding at least .
Cast Phantasmal Image by paying , choosing to have it enter the battlefield as a copy of Palinchron.
Phantasmal Image enters the battlefield, untapping up to seven lands.
Activate Phantasmal Image by paying , returning it from the battlefield to your hand.
Repeat.

You control at least one creature.

Cast Ephemerate by paying , targeting any creature you control.
Holding priority, cast Naru Meha by paying .
Naru Meha enters the battlefield, creating a copy of Ephemerate targeting Naru Meha.
Resolve the copy of Ephemerate, blinking Naru Meha.
Repeat from step 3.

Cast Lotus Petal by paying .
Displacer Kitten triggers, blinking Venser.
Venser enters the battlefield, returning Lotus Petal to your hand.
Repeat.

Cast Chrome Mox by paying .
Displacer Kitten triggers, blinking Venser.
Venser enters the battlefield, returning Chrome Mox to your hand.
Repeat.

You have not cast a spell using Lurrus this turn.

Activate Lion's Eye Diamond by sacrificing it and discarding your hand, adding three mana of any color.
Cast Lion's Eye Diamond from your graveyard by paying .
Displacer Kitten triggers, blinking Lurrus.
Repeat.

You control at least one creature.

Cast Momentary Blink by paying , targeting any creature you control.
Holding priority, cast Naru Meha by paying .
Naru Meha enters the battlefield, creating a copy of Momentary Blink targeting Naru Meha.
Resolve the copy of Momentary Blink, blinking Naru Meha.
Repeat from step 3.

Cast Everflowing Chalice by paying .
Displacer Kitten triggers, blinking Venser.
Venser enters the battlefield, returning Everflowing Chalice to your hand.
Repeat.

Whenever an opponent's creature enters the battlefield, Godhead of Awe sets the creature's base power and toughness to one.
Because Elesh Norn gives all opposing creatures -2/-2, the creature will die as a state-based action due to having less than zero toughness.

Activate Viscera Seer by sacrificing Kitchen Finks.
When Kitchen Finks dies, its persist ability triggers, returning Kitchen Finks from your graveyard to the battlefield with a -1/-1 counter on it.
When Kitchen Finks enters the battlefield, it triggers, causing you to gain 2 life.
Heliod triggers, putting a +1/+1 counter on Kitchen Finks.
Resolve the Viscera Seer ability.
Repeat.

Activate Carrion Feeder by sacrificing Kitchen Finks.
When Kitchen Finks dies, its persist ability triggers, returning Kitchen Finks from your graveyard to the battlefield with a -1/-1 counter on it.
When Kitchen Finks enters the battlefield, it triggers, causing you to gain 2 life.
Heliod triggers, putting a +1/+1 counter on Kitchen Finks.
Resolve the Carrion Feeder ability.
Repeat.

Activate Woe Strider by sacrificing Kitchen Finks.
When Kitchen Finks dies, its persist ability triggers, returning Kitchen Finks from your graveyard to the battlefield with a -1/-1 counter on it.
When Kitchen Finks enters the battlefield, it triggers, causing you to gain 2 life.
Heliod triggers, putting a +1/+1 counter on Kitchen Finks.
Resolve the Woe Strider ability.
Repeat.

"Ouphe" chosen with Metallic Mimic.

Activate Viscera Seer by sacrificing Kitchen Finks.
Kitchen Finks' persist ability triggers, returning it to the battlefield with zero -1/-1 counters on it due to Metallic Mimic.
Kitchen Finks enters the battlefield, causing you to gain two life.
Resolve the Viscera Seer ability, scrying 1.
Repeat.

Use Mindslaver's ability targeting an opponent.
Activate Academy Ruins's ability targeting Mindslaver in graveyard.
Pass to opponent's turn.
Pass to your turn and draw Mindslaver.
Play Mindslaver, use it, and target it with Academy Ruins.

Walking Ballista on the battlefield with a +1/+1 counter on it.

Activate Walking Ballista's last ability by removing a +1/+1 counter from it, dealing 1 damage to itself.
Walking Ballista dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Repeat.