Bloodbriar

The trigger does not care what you sacrifice or why: a token chumping into a sacrifice outlet, a creature on the way to a graveyard payoff, a fading artifact cashed in for value, all of it feeds the same counter. That generality is both the pitch and the ceiling. A 2/3 for is a serviceable but unexciting body on its own, so it earns its slot only where an engine that fires the trigger repeatedly is already assembled. It does no work in a deck that never sacrifices anything; it grows fast in one that sacrifices for free as part of its normal turn. Note the wording: the trigger keys off you sacrificing another permanent, so it has no hand in its own growth and adds nothing to the sacrifice density itself. Its size is entirely a function of what the rest of the board does. Because this is a plain triggered ability rather than something you activate, the counters accrue at any speed your sacrifices fire: a cluster of end-step sacrifice effects can pump it on an opponent's turn as readily as your own. It belongs to the lineage of green creatures that convert a board-attrition theme into a beater, a payoff for a build you were already committed to rather than one you commit to building around. Plain in isolation, sharp inside an aristocrats shell.