Crypt of Agadeem

A graveyard counter dressed as a land: its second ability scales not with permanents in play but with black creature cards already dead, which means it does nothing on an empty graveyard and explodes once the yard is stocked. That sequencing is the whole strategic axis. Reanimator and self-mill decks treat the front half as a clunky tapland tax and the back half as the payoff, dumping a stack of black bodies before paying the two-mana activation to convert that pile into a single huge burst of mana. The asymmetry is deliberate: a land that produces one black on its own, then potentially six or eight on a turn where you've filled the bin, is a ritual stapled to a permanent, and rituals that live in your mana base survive sweepers and counterspells that would answer a one-shot spell. It rewards the kind of deck that was already filling its graveyard for other reasons, turning a resource that decks usually treat as a one-way exhaust pipe into something you can cash twice. The land tax (it enters tapped, and the big activation costs an extra two) is what keeps a potentially absurd output from being free; you pay in tempo up front and in cards in the yard, and only then does the spigot open.