Staff of Eden, Vault's Key

The reanimation clause is the obvious hook, but the tap ability is the stranger design: it rewards you for controlling permanents you do not own, a board state most decks never enter by accident. You get there by stealing things: Control Magic effects, donation cards, temporary theft that never gets given back, opponents' commanders parked under your control. The staff turns that pile of borrowed goods into raw card advantage, one draw per permanent you control but do not own, at will. That makes it a payoff for an archetype that historically struggled to convert theft into a closing engine, because taking an opponent's threat answers their board but rarely refills your hand. The two abilities can feed each other, but only in one direction: reanimate a legendary permanent from an opponent's graveyard and you gain a body you do not own, which counts toward the tap the moment the staff untaps; pull one from your own graveyard and you own it, so it does nothing for the draw engine. The self-exclusion in the reanimation text is tidy legend-rule housekeeping, keeping a second copy from looping the first back out of a graveyard so the recursion stops at one target. Six colorless mana means any deck can run it, but only a deck built to accumulate other people's permanents unlocks the second half; the reanimation alone is a fine rate, and the draw engine is the reason to build around it.