Abandoned Outpost

White gets the dependable half of this deal and pays for the flexible half. The tapped white source is free and repeatable, but the rainbow fix costs you the land itself: a one-shot any-color tap that leaves a permanent dent in your mana count. That structure makes it part of a recurring design family, the sacrifice-to-splash land that gives a primarily mono-white manabase access to a single off-color spell without committing real fixing to the deck. The cost spells out the use case: not a fifth color you cast all game, but a one-time payment toward the splash card you drew and could not otherwise cast. Early-era sets that leaned on graveyard and recursion themes gave the sacrifice clause a second life; feeding a land to the yard fuels threshold and recursion in a way a basic never could. The trade is always the same arithmetic, though, and it rarely favors the patient deck: you enter tapped, you tick toward a single off-color mana, and the moment you cash it in you are down a land. A fixer that subtracts from your land count is a tax most decks would rather not pay, which is why this kind of effect lives at the margins of color-greedy builds rather than the center of any manabase.