Mana Echoes

A quadratic engine wearing a tribal payoff's clothes. The mana it returns does not scale with the creature you cast; it scales with how many creatures you already control that share a type with the one entering, and because the trigger counts the new arrival too, each addition widens the gap between the next copy and the colorless flood it produces. The fifth Goblin entering generates five mana; the sixth nets six, and the curve steepens with every body. The number runs away from itself the moment a single token-maker joins the loop, because every token sees every other token it arrived alongside. That is the card's true home: anything that drops multiple same-typed bodies at once. The combo writes itself once a near-free token engine is involved, since the mana floor only has to clear the cost of replaying that engine for the whole thing to spiral. What kept it off the constructed radar in its own era is the colorless restriction (the output can't pay colored costs) and the dependence on a critical mass of shared types before the trigger means anything. Empty the board and it sits there inert. Fill the board with one creature type and it stops being a value engine and becomes a launch sequence. It reads like a Goblins reward and behaves like a storm enabler, the kind of misfiled design combo players spend years prying open.