Phyrexian Vault

A sacrifice outlet with a price tag, and that price is the whole story. There was an era when Wizards had not yet pinned down how much a card was worth measured in dead permanents, and the answer baked into this artifact is two mana plus a creature plus a tap, all to draw one. That rate looks punishing now, but it captures a design instinct that has aged better than the numbers: the value of turning a creature you no longer need into a fresh draw, independent of the creature's death triggers or what killed it. The activation cost is steep precisely because the effect is repeatable and runs at instant speed; you can hold it open as a pseudo-combat trick, sacrificing a blocker mid-combat to dig for an answer, or empty a board of expendable tokens into cards across a long game. The outlet does not care what it eats, which puts it in the family of free-floating sacrifice engines that later sharpened into cheaper and faster forms once the card-economy math came into focus. As an artifact it asks nothing of your colors, which explains why the function kept reappearing in spirit if not in name: the conversion of bodies into cards is colorless infrastructure that any deck can lean on, no matter what it is built around.