Cards marked with "~" are cards I'm considering for cut and/or upgrade.
TheTentacleGang
Artisan of Kozilek: Huge beater with Annihilator 2 that can also get us a creature from our graveyard.
~Conduit of Ruin: Acts both as a cost reducer and a tutor. We'll inevitably have to hardcast #TheTentacleGang every once in a while, so the cost reduction can definitely come in handy. The tutoring aspect also lets us choose what Kinnan, Bonder Prodigy will cheat into play next, assuming we don't draw a card before we can activate him.
Emrakul, the Promised End: Huge, flying beater that can't be countered or targeted by instants. Can also screw over an opponent of our choice.
It That Betrays: Huge beater that makes Annihilator (which it conveniently has) much more potent.
Kozilek, the Great Distortion: Huge, hard to block beater that draws us cards. Does not have Annihilator, but potentially allow us to counter problematic spells.
Kozilek, Butcher of Truth: Yet another huge beater that draws us cards. This one boasts Annihilator 4 and is also one of our only tools against mill decks.
Pathrazer of Ulamog: Huge, hard to block beater with Annihilator 3.
Ulamog, the Ceaseless Hunger: Huge, indestructible beater that exiles on cast. Does not have Annihilator, but mills our opponent for a considerable amount every time we attack with it.
Ulamog, the Infinite Gyre: Yet another huge, indestructible beater. This one destroys a permanent on cast and boasts Annihilator 4. This also is one of our only tools against mill decks.
Void Winnower: Huge beater that not only taxes our opponents while leaving us unaffected, but also makes it hard for them to block effectively.
Ramp
Arcane Signet/Simic Signet/Talisman of Curiosity: Good ramp for the CMC and taps for both of our colours.
Basalt Monolith: Part of an infinite mana combo and also pairs well with Kiora's Follower.
Birds of Paradise: Great ramp for the CMC and taps for both of our colours.
Elvish Mystic/Fyndhorn Elves/Llanowar Elves: Great ramp for the CMC.
Fellwar Stone: Good ramp for the CMC that almost always taps for at least one of our colours, if not both.
Growing Rites of Itlimoc
: Turns out even the poor man's version of Gaea's Cradle is insane.
Gyre Engineer: Great ramp for the CMC and taps for both of our colours.
Ilysian Caryatid/Incubation Druid: Good to great ramp for the CMC and taps for both of our colours.
Maraleaf Pixie/Quirion Elves: Good ramp for the CMC and taps for both of our colours.
Paradise Druid/Sylvan Caryatid: Good ramp for the CMC and taps for both of our colours with built-in protection.
Sol Ring: Amazing ramp for the CMC.
Springleaf Drum: Amazing ramp for the CMC and allows us to get a use out of our utility creatures.
Thought Vessel: Good ramp for the CMC. No maximum hand size will prove useful every other game.
CardAdvantage
~Abundance: While not technically card advantage, this becomes really useful in the mid game to make sure we never hit lands when we don't want to, and vice versa.
Arcanis the Omnipotent: Especially good with haste and gets ridiculous if left unchecked. Pairs extremely well with Seedborn Muse.
~Guardian Project: This deck includes a high percentage of creatures, which obviously goes hand in hand with this card. Creatures that ETB via Kinnan, Bonder Prodigy's ability will also trigger this.
Mystic Remora: Aggressively costed, this can be played in the early game to draw us a ton of cards while people are trying to ramp and set up their game plan. Even in the late game, the 4-mana tax means you'll almost always draw some cards or at least deter your opponents from playing non-creature spells.
Nezahal, Primal Tide: Unconditional version of Mystic Remora, without the cumulative cost and on a BigBoi body that's hard to get rid of. It also can't be countered and removes your maximum hand size. Yeah, this is pretty sweet.
Prime Speaker Zegana: With almost any of #TheTentacleGang on the battlefield, this will draw you a lot of cards and leave you with a BigBoi to boot!
Prophet of Distortion: Allows us to draw our entire deck if we achieve infinite colorless mana.
Rhystic Study: The non-cumulative upkeep version of Mystic Remora. This triggers on all spells and not just non-creature, but the 1-mana tax is much easier to pay.
Teferi's Ageless Insight: This is basically the good part of Alhammarret's Archive for 1 less mana. Doubling our draw is just ridiculous when paired with literally any other cards in this category.
Tishana, Voice of Thunder: Considering the number of mana dorks we can have on the board, this draws us a lot of cards. The no maximum hand size and BigBoi body is just a bonus.
Tutor
Drift of Phantasms: Transmute lets us tutor for Freed from the Real, Pemmin's Aura & Basalt Monolith, 3/5 combo pieces. Can also get us Growing Rites of Itlimoc
or Rhystic Study.
~Fauna Shaman: Allows us to discard unneeded creatures (mostly mana dorks) for better ones depending on the state of the game.
Muddle the Mixture: Transmute lets us tutor for Kiora's Follower & Crashing Drawbridge, 2/5 combo pieces. It can also be used to tutor Fauna Shaman if we need a specific creature as well as Lightning Greaves, Swiftfoot Boots, Cyclonic Rift & Heroic Intervention and even, God forbid, act as a counter spell if we're in a pickle.
Protection
Asceticism: Gives all of our creatures Hexproof and allows us to regenerate them if needs be.
Heroic Intervention: Kind of like a much cheaper one-time use Asceticism at instant speed.
Lightning Greaves/Swiftfoot Boots: Shroud/Hexproof protects #TheTentacleGang quite effectively, but giving them haste is the reason why we are running these. Can also give haste to Crashing Drawbridge which makes it a one-sided Concordant Crossroads.
Interaction
Counterspell: The good ol' "counter any spells" by which all other counter effectiveness is measured.
Narset's Reversal: Someone tries to counter you? Bounce your spell back to your hand and not only make their counter fizzle but also cast your spell anyway; you can even recast it next turn! Someone plays an overloaded Cyclonic Rift? Not this turn they aren't; you are! Maybe you just want to copy your own spell over 2 turns; well, now you can!
Flusterstorm/Swan Song: Very low CMC, albeit narrow-ish. However, instants and sorceries are generally what we want to counter anyway.
Removal
Beast Within: Can target any permanent. The 3/3 is inconsequential.
Chain of Vapor: You can either use this to bounce a problematic permanent or to save your own from targeted removal. If used on your own permanent, you can sacrifice a land and bounce one of your opponents' permanent as well, making this a 2-for-1. Can also be used to bounce multiple threats by targeting the second scariest thing on the board, forcing its owner to sacrifice one of his lands to take care of the number 1 threat.
Cyclonic Rift: The only way to reset the board while leaving us unaffected. I don't think I need to explain why this is good.
Nature's Claim: Very low CMC, the 4 life is inconsequential.
Pongify/Rapid Hybridization: Very low CMC. The 3/3 is inconsequential.
Utility
Biomancer's Familiar: This reduces the activation cost of Kinnan, Bonder Prodigy, allowing us to activate him more easily/often. It's especially good with Seedborn Muse.
Crashing Drawbridge: Gives mass haste to our board. Mainly used to close out the game when cheating a bunch of creatures with Kinnan, Bonder Prodigy but can also be used to chain mana dorks.
Freed from the Real/Pemmin's Aura: Allows us to generate infinite when cast on a mana dork that can produce . Can also be used on Kiora's Follower if we have a mana rock that can tap for . Pemmin's Aura also doubles as protection since it can give Shroud to the enchanted creature.
Kiora's Follower: Allows for some infinite mana combos and general ramp as well as general value by untapping utility creatures such as Fauna Shaman or Arcanis the Omnipotent.
Leyline of Anticipation: Allows us to play everything at instant speed. If we're lucky, we may not even have to cast it. Obviously pairs extremely well with Seedborn Muse.
Seedborn Muse: This card makes it very easy to keep mana open for interactions and lets us activate Kinnan a whole lot. As stated above, this becomes extremely powerful if we have either Leyline of Anticipation or Alchemist's Refuge on the battlefield.
Lands
Alchemist's Refuge: Allows us to play everything at instant speed. Pairs extremely well with Seedborn Muse.
Reliquary Tower: You'll draw a lot of cards and this will prevent you from discarding to 7.
Simic Growth Chamber: I generally avoid bounce lands, but this lets us go infinite with Kiora's Follower + Freed from the Real/Pemmin's Aura.
Tolaria West: Allows us to tutor for any of our lands. Also tutors for 0-CMC mana rocks if you have the budget for them. I don't count this towards the land total.
*You may think this is a lot of lands considering the amount of ramp we're packing, and it kinda is. However, while mana dorks/rocks are fast, they aren't all that resilient. This deck is also extremely coloured mana hungry.
Notable Exclusions
Land ramp (e.g. Cultivate) → I would only ever add these if you are in an extremely creature removal heavy meta since they are considerably slower thank dorks and rocks, albeit more resilient. To be honest, though, I would simply choose another commander if that were the case.
Arixmethes, Slumbering Isle → While a 12/12 is thematically fitting in this deck, it might be too slow to include considering Kinnan will not increase its mana production ability until we can deplete the 5 counters.
Nyxbloom Ancient/The Great Henge → These might be worth it in a slower meta, but I found the greater amount of mana produced does not matter at the point in the game these would come out.
Thrasios, Triton Hero/Thassa's Oracle/Walking Ballista → Extremely efficient and compact win conditions that can end the game on the spot if you achieve infinite mana. As already stated in the introduction, my intention was never to create a cutthroat combo deck, which is why these cards aren't included.
