Fathom Fleet Captain

The gate is the whole design: the attack trigger fires only when you already control another nontoken Pirate, so a two-drop with menace asks the deck to do its tribal homework before this card pays out. Deployed alone, it is a simple evasive body; standing beside real Pirates, it converts surplus mana into a fresh 2/2 with menace each combat. The nontoken clause is what keeps that from spiraling: the tokens the Captain makes are Pirates, but they cannot satisfy its own requirement, so you cannot bootstrap an army off the tokens alone. The card needs genuine bodies committed first, and the tokens it produces exist to widen the board and feed other tribal payoffs rather than to refuel this one. The trigger also checks only on the Captain's own attack, once per swing, which sets the pace: this is a slow mana sink, not a burst engine. That combination (cheap enough to land early, scaling into a menace-heavy board late, gated behind a real creature you had to commit to first) is the familiar shape of an aggressive tribal payoff built around a mana sink. Assemble the creature type ahead of it and the Captain compounds every turn; skip the tribal shell and the trigger simply never turns on.