Umbral Collar Zealot

A free, repeatable sacrifice outlet with a body attached, and the free part is the whole strategic proposition. The activation costs no mana and has no cap, so any creature or artifact you no longer need (a spent token, a chump blocker, an artifact whose job is done) converts into a surveil at instant speed. That matters more to aristocrats builds than the modest filtering suggests: an unconditional, repeatable outlet is exactly the piece those decks tend to be short on, and here it arrives on a 3/2 for two mana that can at least trade in combat if nothing better is happening. The surveil is almost incidental to the outlet, though it does feed graveyard-matters shells by loading the yard on your terms. Because the ability neither taps the Zealot nor requires its fodder to stay untapped, it stays live across the entire turn: it can cash in a creature the moment something threatens to kill it for free, or fire during your own combat to trade an attacker for value before damage rather than let it die for nothing. As a Cleric it sits in black's long line of self-sacrifice enablers, but where many of those charge mana per activation or limit the number of uses, this one asks only that you have something worth eating.