Aethershield Artificer

The +2/+2 is the lure; the indestructible clause is the work. The critical detail is the timing: the trigger fires at the beginning of combat on your turn, which makes this an offensive tool, not a defensive one. It cannot save a creature from a removal spell cast during your opponent's turn, and it does nothing while the artifact you want to protect sits untapped, waiting for a sorcery to resolve before you ever get a combat step. What it does instead is make one attacker of yours untouchable for a single turn: point it at whatever artifact creature is about to swing, and that creature ignores destroy effects and lethal combat damage until end of turn, turning a profitable double-block into a one-sided trade and forcing an opponent to spend an instant-speed answer or eat the hit. The ceiling is gated by two honest restrictions. The buff lands on exactly one target per combat, so it shields a linchpin rather than a team. And because the Artificer itself is a Dwarf, not an artifact, it can never protect itself: the card is built as a bodyguard for someone else's engine, never its own centerpiece. Strip away the artifact creatures worth defending and the whole thing collapses into a 3/3 with a trigger that has nowhere useful to go.