Bazaar Krovod
The untap rider is what separates this from the dozens of toothless toughness pumps it superficially resembles. The trigger goes on the stack as attackers are declared and resolves before blockers come down, so the chosen attacker untaps the instant it's committed to the swing: it effectively gains vigilance for that combat. That's the wrinkle. A creature you'd normally hold back as a blocker can now go on offense and still be standing, untapped, when the opponent's crack-back arrives. The +0/+2 is there to keep that newly multitasking attacker alive through whatever it ran into, not to force damage through. And because the Krovod itself is a 2/5, it's built to keep attacking without dying, which is precisely what keeps the trigger live across turns: a slow, durable engine that only pays off when the board is wide enough for the untap to mean something. It belongs to the white tradition of designs that ask the wider battlefield to do the work, contributing defense and a tempo trick rather than raw stats. The effect is narrow enough that it never warped anything, but granting a one-turn vigilance through an attack trigger, on a creature that itself is too sturdy to die in the exchange, is a more interesting idea than the modest toughness boost it's wrapped inside.
