Thrasios, Triton Hero

What pushed this Merfolk into the permanent fixtures of multiplayer deckbuilding is not the body, which is a 1/3 that never attacks, but the colorless price tag on its activated ability. Because the cost is with no green or blue pip, the engine doesn't actually require the colors of the card that houses it: any mana ramp from any source feeds it. That is the structural trick. Partner lets a two-mana commander occupy half of a command zone while contributing nothing to the board, so it is free to share the slot with a value or combo half from any color identity, and the four-generic outlet means whatever mana you accumulate eventually converts into cards or lands without bottlenecking on a color requirement. The smoothing is real too, but it happens inside a single activation: scry 1 arranges the top card, then that card is immediately revealed, hitting the battlefield tapped if it's a land and drawn otherwise. You are not setting up a future turn; you are choosing, right then, whether the next mana buys you a land drop or a fresh card. Most legendary creatures sell themselves on what they do early; this one sells on what it does with surplus, late, when a long game has produced more mana than any single spell can absorb. It is the colorless mana sink wearing a green-blue costume, and that costume is the only thing tethering it to its colors at all.