Metalcraft

Cards printed with the metalcraft keyword, which switches on a stronger mode while the controller has three or more artifacts on the battlefield. Galvanic Blast deals 4 damage instead of 2, Dispatch exiles instead of tapping, Etched Champion gains protection from all colors, and Mox Opal taps for any color. Narrower than artifacts.artifact_payoff, which covers any card that scales with artifact count; metalcraft is specifically the named Scars of Mirrodin threshold ability and excludes generic artifact-count rewards that use other templating.