Myr Retriever

Its job is to die. The trigger reads "another target artifact card," and that one word is the entire design: it can never rebuy itself, so it always needs a partner waiting in the graveyard. Two copies plus a free sacrifice outlet weaponize exactly that constraint: each dies, returns the other to hand, you recast for cheap, and the loop costs only mana per cycle. On its own that exchange just shuffles the two Retrievers back and forth. The recursion becomes an engine the moment you bolt on a third effect that converts those repeated deaths into something else: Scrap Trawler chaining returns down the curve, an aristocrat drain pinging on each sacrifice, a separate return effect feeding a combo piece back to hand. Structurally it converts a permanent on the battlefield into a card in hand at the instant it dies, the same battlefield-to-hand recursion that recurring black value creatures get on upkeep or attack, but routed entirely through the artifact subtype and triggered by removal rather than by a phase. The artifact-matters design space that first gave it a graveyard deep enough to draw from has only widened in the years since this kind of card appeared, and the trigger has aged into a load-bearing node wherever artifact recursion meets a sacrifice outlet. The best line is still the oldest one: get it killed, on purpose, again.