Tempered Steel

The payoff that white artifact aggro was built around: a single enchantment that turns a board of 1/1 tokens and undercosted metal bodies into a lethal team for three mana. Anthem effects predate it by years (Glorious Anthem, Crusade), but those keyed off a creature color or type; keying off the artifact card type instead forces a deckbuilding commitment rather than offering a generic finisher. The +2/+2 runs steeper than the usual anthem step because the pool it touches is narrower: you only collect the payoff if your board is built almost entirely from metal. That trade is the whole design. In a deck running Memnite, Ornithopter, Signal Pest, and a flood of artifact tokens, doubling or tripling each body's power converts a wide-but-fragile board into a clock that races almost anything, and a second copy stacks linearly. Its resilience is the quieter half of the appeal: because the buff lives on an enchantment rather than a creature, it survives the symmetrical creature wipes that would clean up the board it pumps, so the anthem stays online to power the rebuild. The catch is the obvious one: clear the artifacts and the enchantment sits inert, and it asks you to commit fully to the plan. That is exactly the deal an aggressive artifact deck is happy to take.