I started playing this game the spring before the first Commander sets released, but was well acquainted to the format before that set dropped. My first foray into the format was a Karrthus, Tyrant of Jund deck, and Karrthus will always hold a spot in my heart, but my first love was Riku of Two Reflections. I remember it vividly. Riku was nearly the last Commander to get revealed and by that time in preview week I had my hopes up for something good in what I knew would be my favorite color combination, and boy did they deliver. I remember the moment it was revealed I texted my friends saying, "This is perfect, literally all I've ever wanted."
So I made that deck, and spent all of college making improvements to it until it was a hyper-resilient winning machine, until one day, the unthinkable happened. Primeval Titan was banned. I never knew this one card meant so much to the deck. Surely, Riku would survive. Unfortunately the deck was just too mana hungry to persist and my favorite legendary creature ever was relegated to the box. Eventually I got fed up with letting it rot in a box and pulled it back out, starting from scratch, with my newfound 6x10 philosophy of deck building I began putting cards together until this amazingly fun mishmash of synergies came together. Here's a card-by-card breakdown of what is currently one of the most enjoyable decks I've made. It's nowhere near as strong (in terms of win percentage) as the original, but it sure fulfills the spirit of the format.
Ramp:
Sol Ring: an EDH staple, leads to explosive openers, etc. Tutorable with Trinket Mage
Sword of the Animist: an underestimated but incredible ramp option. Usually represents between 2-6 lands
Coiling Oracle: A pet card, the oracle represents so much value for only 2 mana. It always replaces itself and sometimes becomes so much more. Holds the sword and Skullclamp well
Cultivate and Kodama's Reach: lumping these two together. Fix colors, get ahead of the curve, never a bad card.
Explosive Vegetation: 7 mana is really where the deck starts to take off and veggies help get there like nothing else can
Solemn Simulacrum: having access to a colorless, manafixing, card advantage, rattlesnake is amazing for only 4 mana
Garruk Wildspeaker: Ravnica block bounce-lands make Garruk truly insane. Ramp when it's relevant, and a very serious win-con in one package. Making tokens is the oft-forgotten ability on this Garruk, but with the token synergies in this deck, it is a viable option
Urban Evolution: 5 mana seems like a lot for this effect, but it's never a dead card, and with Riku in play, it becomes one of the most incredible effects available
Ulvenwald Hydra: do I wish this card was Primeval Titan? Maybe, but it scales into the late game in a way that Titan didn't and certainly plays defense better
Removal
Trygon Predator: sometimes this card eats 3-4 cards. Sometimes all it eats is removal. Either way it punishes greedy Sol Ring hands and gets rid of removal that could have otherwise been directed at Riku or another high-value target
Krosan Grip: if you've never seen a table react to the phrase, "Grip your Top" you haven't experienced all this game has to offer. In all seriousness, there are so many artifact and enchantment related infinite combos, and Krosan Grip puts a hard stop to them all
Voidslime: a seriously spectacular counterspell; stopping Tooth and Nail, Ashnod's Altar, and annihilator all in one card
Rewind: a "free" counterspell on other's turns, and a way to protect myself while sometimes netting mana in the process on my turn
Decimate: basically read this card as "if an opponent controls an enchantment, destroy it and a target creature, artifact, and land" because enchantments are the hardest requirement to fill on this card. Then ask yourself, would I pay 4 mana for that effect. I would, and do
Mystic Snake: a great tempo spell and soft-lock with Deadeye Navigator or Crystal Shard
Flametongue Kavu: usually this card is able to handle no less than 2 of my opponents' creatures and sometimes more
Acidic Slime: deals with problematic permanents and threatens to trade with just about any creature my opponents attack me with
Icefall Regent: this used to be a Frost Titan but the evasion on this creature is often-times more relevant
Phyrexian Ingester: a huge beater that exiles cards like Avacyn, Angel of Hope in the process
Finishers
Plasm Capture: doesn't inherently win the game, but typically gains so much mana that I'm able to get ahead and defend that lead until the game ends
Deadeye Navigator: I don't think this card warrants a ban, but I am aware of its strengths. I don't run most of the infinite combos with it anymore because the game wasn't fun when everything was just "deadeye paired with Palinchron". Besides, this card can usually generate enough card advantage to effectively close out a game without going infinite
Synthetic Destiny: This card is like a one-sided Warp World that can't miss on instants and sorceries. Resolve it once and you end up in the lead; twice, and you should end the game almost immediately. Remember that your stuff doesn't come back until end of turn.
Walk the Aeons: the only extra turn effect I play. The flexibility of taking one, or two if at a cost, extra turns is worth 6-mana
Pathbreaker Ibex: this card is like an Overrun with suspend 1, that can even better when cloned, or boosted
Cyclonic Rift: technically I guess this card operates as an answer, but usually it opens everyone up for attacks while stopping me from dying to a lethal attack
Avenger of Zendikar: is this card clever and original? Absolutely not. However, its brutally efficient and gets out of hand faster than you can blink
Terastodon: This is also a flexible removal spell, but can crush people trying to get back into the game, and that makes it a win condition in my book
Insurrection: this card is not creative and does not need to be. More so than just about any other single spell, this one ends games in spectacular fashion
Ulamog, the Infinite Gyre: this is an especially strong win condition against poorly constructed mill decks. If the game gets down to 1v1, I would rather have this creature than just about anything else in my deck
Tokens
Arachnogenesis: this card often puts no less than 4 creatures into play while protecting my life total. For 3 mana, that's insane value
Pia and Kiran Nalaar: Sometimes I wish this was a Siege-Gang Commander, but sometimes the flying tokens are more relevant
Flameshadow Conjuring and Splinter Twin: a pseudo Clone that combos with the next two cards. Sometimes Riku gets dealt with 5 times in a game and these cards act as redundancy for him
Parallel Lives and Primal Vigor: untap with one of these and almost any other card in the deck and you'll find it hard to lose the game
Spitting Image: this card lets you use Riku's ability on other people's creatures while turning those late-game lands drawn become the best creature in play
Progenitor Mimic: synergistic with token doubling effects, this one card also threatens to take over the game if unanswered
Drowner of Hope: token creation that can also lock peoples' creatures down for long enough to swing the game around
Hornet Queen: this card puts 5 deathtouch blockers into play on its own. Combine it with any of the token doubling effects or Clone effects and it stop everyone from attacking me
Card Advantage
Skullclamp: there are a lot of tokens in this deck and Skullclamp helps turn them into a fresh hand. Outside of maybe Consecrated Sphinx there just isn't another more efficient way to draw a whole bunch of cards. Tutorable with Trinket Mage
Exclude: most of the ways people will try to win the game is on the back of creatures, so the fact that this is more narrow than Dismiss is hardly relevant. To make up for that lack of diversity, this card is significantly easier to cast
Eternal Witness: so much has been said about this card that it seems futile to say more. Efficient way to get back something that's either been countered or previously played
Trinket Mage: only has 3 targets, but every one is something that I want to see at some point in the game
Fact or Fiction: I have a little advice to deck building: when you can, play cards that are good at every stage of the game. Fact or Fiction is one such card
Kiora, Master of the Depths: what was true for Garruk is mostly true here too, except Kiora tends to be a better top deck if my hand is empty
Mulldrifter: I would not play Divination and I would be hard-pressed to play a kicked Citanul Woodreaders but a split card that had either effect is something I would
Greenwarden of Murasa: What was true for Eternal Witness is true for Greenwarden, except this card can do that twice, while also getting in for more damage
Prime Speaker Zegana: the most conditional draw spell in the deck, but she represents between 2 and 6 cards in exchange for 1 card most of the time
Sphinx of Uthuun: Fact or Fiction is good. Sphinx is a Fact or Fiction that can be Cloned or bounced with Deadeye Navigator
ETB Synergy
Voyager Staff: for 3 mana total this one card can protect Riku or re-trigger any ETB (Enter the Battlefield) effect. Tutorable with Trinket Mage
Phantasmal Image, Dack's Duplicate, Clever Impersonator: additional copies of the best creature in play, mine or my opponents. Image is cheap beyond belief, Duplicate has haste, and impersonator can be any other permanent as well
Proteus Staff: only useable at sorcery speed is worth the fact that tokens can be cashed in for a new, better creature, or an opponent's best creature can become something less scary. The flexibility to do either or both makes this card a fantastic inclusion
Crystal Shard: protects Riku, re-triggers ETB effects, and can blow out unsuspecting opponents who tap out
Eldritch Evolution: such a cheap way to turn creatures into better ones
Identity Thief: re-trigger your own ETB effects or get rid of blockers for a turn. The flexibility to do both justifies this card's place in the deck
Body Double: sometimes the creature you really want to copy ends up in a graveyard. Body Double solves that problem for you
Summoning Trap: punishes counter-happy opponents, or can be used to plop something unexpected into play at the end of someone else's turn. Again the modal nature of this card makes it go from okay, to excellent
Saheeli's Artistry: typically this is at worst Sol Ring plus something else. That's a good worst case scenario