This might not be a very good cube tbh

Latest:
...I kicked out all the cards with Terese Nielsen and Noah Bradley art. If you want to argue about this go draft something else.
...Gruul is now "Maybe I should play 19 lands.dec". Toss 'em with Borborygmos, ramp 'em with World Shaper, retrace 'em, whatever you wanna do. It kind of likes what the green golgari cards were trying to do, so now a few cards do double duty, which is exactly what I want the cube to do.
...Dimir is now "I'm playing your deck.dec". See: Dimir Doppelganger, Thief of Sanity, Nightveil Specter, Hostage Taker. Even though Dimir has the fewest cards tagged as being "for Dimir," Blue and Black are colors that have the most "guildless"-tagged cards, so Dimir can play a more flexibly-framed control type of deck with fewer bombs and more answers.
...Swapped some token generators to instead make more knights and more elves to exploit some synergies, but if you play them without the synergy there should be no downgrade. Looking into saprolings next. Update: Thelonite Druid and Tendershoot Dryad came in so saprolings are probably nutty now.

Design Notes:
...The 'signpost' cards are the gold cards. Basically, if you look at Drown in Filth, Grisly Salvage, and Journey to Eternity, then you can figure out that drafting black and green will lean into a 'reanimator'-style deck.
...Each color combo should have a neat setup -> payoff:

Azorius:
Setup: Resolve permanents with ETB and/or LTB effects.
Payoff: Blink said permanents with Flicker effects.
Representation: A
Improvement plan: Probably none necessary.

Dimir:
Setup: Resolve spells that interact with opponents' deck.Payoff: Copy/steal opponents' powerful creatures or spells.
Representation: CImprovement plan: May not be necessary. Blue and Black have 'guildless' cards that enable the plan.

Rakdos:
Setup: Resolve creatures that benefit from the player sacrificing them or other permanents.
Payoff: Steal opponents' creatures and sacrifice them.
Representation: A
Improvement plan: Watch M21 for repeatable effects like Captivating Crew.

Gruul:
Setup: Draw or mill lots of lands and use them as ammo.
Payoff: Toss lands with Borborygmos or Seismic Assault, use them to retrace useful cards for repeatable effects, mill them for your Ruination Rioter
Representation: C
Improvement plan: Looking to Turf War / Lands decks for inspiration.

Selesnya:
Setup: Create lots of tokens.
Payoff: Pump the tokens with anthem effects to go taller or duplicate the tokens to go wider.
Representation: A
Improvement plan: Testing needed.

Orzhov:
Setup: Become the Monarch, or resolve creatures with the Extort or other tax-like effects.
Payoff: Burn out the opponent with repeatable drain effects.
Representation: D
Improvement plan: Vindicate means Orzhov gets one fewer slot for no reason. Fix, somehow!

Golgari:
Setup: Fill own graveyard with creatures.
Payoff: Reanimate said creatures
Representation: A
Improvement plan: Reevaluate reanimation spells.

Simic:
Setup: Ramp mana, resolve permanents with alternate-win abilities.
Payoff: Pump enough mana into the alternate win cons before the opponent can remove them
Representation: C
Improvement plan: May not be necessary. Green and Blue have 'guildless' cards that enable the plan..

Izzet:
Setup: Cantrip many instants and sorceries into the graveyard.
Payoff: Attack with creatures that benefit from spells in the graveyard or cast this turn.
Representation: A
Improvement plan: Probably none necessary.

Boros:
Setup: Cycle many permanents into the graveyard.
Payoff: Resolve spells that benefit from the player cycling cards.
Setup: Resolve creatures that redirect damage to players.
Payoff: Resolve board-wiping burn spells to redirect huge damage to the opponent.
Representation: B
Improvement plan: This seems underpowered but fun regardless, I guess? Maybe?

Testing Notes:
...Splashing a third color to take the "gold glue" to make color pairs blend together is fun and interesting. Splashing to take instawin gold bombs is boring. Gold cards' focus should be to glue the colors together without giving you wins by themselves.
...On a similar topic, it's okay for not-glue cards to be in the gold slots if they're answers like Vindicate.
...On a similar topic, I definitely should put in more removal.

To Do:
...Do I have enough removal? Creature kills, disenchants?
...Do I have enough 1-drops? Does red really need things like Goblin Guide to compete?*Do I have enough mana ramp? Dorks/accel?
...Do I have enough french vanilla keywords? Trample, First Strike, Vigilance, Flying/Reach?
...Do I have enough combat tricks? I'm defining this as "spells that are fun to cast during combat"
...Do I have enough interaction? After solving for Removal and Combat Tricks, this leaves the need to check for hand control like discard spells and counterspells.
...Develop a "provided information" list. Probably includes "Look at the gold cards, they do the thing" and a list of archetypes. Progress: I sort of did this and included it above but it could be more concise for actually playing with.
...Develop a "false meta signals" list. This is stuff like "Don't take Dark Depths expecting to find Vampire Hexmage later, don't expect cycling to be a mechanic supported across all 5 colors", etc
...Wait for WotC to complete that horizon canopy cycle, those are some good lands right there