Darksteel Relic

Strip every line off the card and you are left with a curiosity: a permanent that costs nothing, does nothing, and cannot be destroyed by destruction effects. It is the answer to a question almost no deck asks, which is exactly the point. The free cast means it enters with zero investment, so it triggers, populates, and counts toward artifact-matters effects without ever drawing tempo from the rest of the hand. The indestructibility means it survives the most common board-clearing template (the one that says "destroy"), surviving as a stubborn permanent that has to be exiled, bounced, or sacrificed away rather than swept. That combination makes it a piece of pure scaffolding: a permanent whose only job is to exist on the battlefield as the cheapest possible body for some other effect to read. Affinity counts it for one. Metalcraft counts it as one of three. Any "sacrifice an artifact" cost finds a free one waiting. It is design at the boundary, the point where a card carries no text worth playing for its own sake and instead becomes a token-with-a-frame: a permanent that opts out of doing anything so that it can reliably be there when something else needs an artifact to point at.