Academy Ruins

Recursion that never runs dry. The activated ability buys back an artifact card to the top of your library each turn, which makes it the colorless-toolbox land for any deck whose engine lives in its artifacts: a Mindslaver lock, a Crucible-style land loop run through artifact lands, a slow grind where every key piece comes back the moment it dies. The cost is steep enough to stay fair: one generic and one blue, plus the tap, plus a draw step to actually recast what you put back. That tempo tax is the whole balancing act. You are spending a card draw and three mana across two turns to reuse something you already own, which is brutally inefficient as raw tempo and exactly the kind of inevitability that wins attrition games where tempo no longer matters. It demands nothing in deckbuilding beyond running enough artifacts worth retrieving, since it produces colorless mana when you are not activating it. The closest functional cousin is the way certain green effects rebuy lands from the yard turn after turn; this does the same structural work for artifacts, in a single legendary land, at instant speed. For decks built to outlast rather than outrace, that recurring loop is the difference between running out of resources and never running out at all.