Eden, Seat of the Sanctum

A colorless land that taps for one and, once you invest five more, becomes a one-shot regrowth for any permanent card sitting in your graveyard: creature, artifact, planeswalker, or otherwise. The design work is all in how the sacrifice is gated. The mill-two resolves before the payoff: it fills the yard the land will then reach back into, and it also feeds whatever graveyard synergies you happen to be running. The sacrifice is optional, which matters more than the numbers suggest. You mill first, and only after seeing the two cards do you decide whether to trade the land in and recur something. Because the return rides a linked triggered ability rather than living inside the activation itself, the mill resolves even when you keep the land, so the ability doubles as a slow self-mill engine you can run for turns before you ever cash it in. The rate is deliberately steep: five mana and a land slot to get back a single permanent, all funneled through one activation. What that price buys is redundancy and reach. It is a recursion effect no color has to pay for, hosted by a card that any deck can play, and it answers the entire permanent class rather than just creatures. That breadth is where a land like this justifies itself against the narrower single-color Regrowth-style effects it competes with.