Memorial Vault

Card advantage that scales with what you feed it, gated behind a tap and a sacrifice. The trick lives in the "one plus" clause: even a humble mana rock returns cards proportional to its own value, so an artifact you were going to crack for mana anyway becomes a second engine that converts it into raw cards. That reframes the sacrifice not as a loss but as a trade-up, and it rewards a deck already churning through mana rocks, Treasures, and disposable equipment. The tap symbol is doing quiet but firm balancing work: only one activation without a way to untap, so this is not a fodder-shredder that eats a wide board in a single go. You get one bite, and the bite is only as big as the artifact you're willing to give up, which pushes you toward feeding it your fattest expendable rock rather than a pile of tokens. The other governor is the "this turn" window: the exiled cards have to be played before end of turn or they evaporate, so it banks nothing. You spend the value the moment you dig for it. It reads as a slow value piece but plays as a tempo burst: the payoff peaks when you trade a high-mana-value artifact into a fresh handful and actually deploy all of it before the turn passes.