Machinesmith Automaton

A 2/2 for three is a starting position here, not a rate: this is an artifact-count payoff that grows itself, banking a +1/+1 counter every time another artifact enters under your control. The trigger fires on any artifact entering the battlefield, not just cast artifact spells, so a Treasure minted mid-combat, a Thopter spat out by a token engine, or a copied artifact each feeds the counter just as reliably as a hard-cast permanent. The design puts the whole engine on one card, which means the deck around it does not need a separate anthem or a sacrifice loop to convert board volume into damage; it just needs artifacts, and enough of them entering across a turn to swing the trample math. Trample is what turns that scaling into a clock rather than a stalemate: a chump blocker in front of a growing artifact creature only postpones the overflow. That pairing (a self-scaling body plus evasion that keeps pace) is a familiar red-and-artifact shape, but bundling both onto a three-mana creature is aggressive, because the counters are permanent and stack turn over turn. Every trigger is worth the same +1/+1 regardless of what caused it, so the card rewards flooding the board with cheap artifacts and token-makers over any single expensive one. It flattens the deckbuilding question to a single axis: how many artifacts can you reliably land after this hits the table, and how fast.