Adarkar Valkyrie

The tap ability turns a single creature on the board into a contingent reanimation target, including your opponent's. Point it at a blocker before damage, at a creature you are about to sacrifice, or at the best thing your opponent stands to lose this turn: if that specific creature dies after the activation, it returns under your control, no mana required. The sequencing is the engine. Because the trigger only arms the recursion (you tap on a chosen creature, and that creature alone returns if it dies later in the turn), it pairs naturally with removal and edicts: kill their threat with your spell, steal it with the Valkyrie. The cost it pays for being a repeatable steal-and-reanimate is that tapping arms only one creature per activation, and the named target has to actually die that turn for anything to happen (which also means tokens, gone for good once they hit the graveyard, are not legal returns). Vigilance does quiet structural work: the body keeps attacking while the ability stays available, so pressure and the value loop are not competing for the same turn. As a flying 4/5 it survives most of what it wants to feed on, which is what makes the activation reliable rather than a coin flip. The design sits in white's "creatures die and come back" lineage, but it aims the recursion at the opponent's board rather than just rebuying its own dead, an aggressive read on a color usually content to recur what it loses.