Slagstone Refinery

The Powerstone-era design instinct was to make artifacts pay you when they leave, and this is the engine that converts attrition into acceleration. Sacrifice outlets, board wipes, and enemy removal usually punish a permanent-heavy deck for overcommitting; here every nontoken artifact that hits the graveyard or gets exiled from the battlefield hands back a tapped Powerstone. The clause covers itself, too, so blowing up your own board (or having it blown up) still nets mana. That reframes what an artifact loss costs: instead of a body traded away, it becomes ramp that carries into your next artifact spell. The nontoken clause is the discipline that keeps the engine grounded: it will not launder your Treasures or Powerstones back into more Powerstones, so the mana comes from spending real artifacts, not from recycling disposable tokens. The Powerstone restriction narrows things further, since the mana can't be spent to cast a nonartifact spell, so the engine feeds itself rather than opening the door to arbitrary big turns. The strongest shells here treat their own hard-cast artifacts as ammunition rather than a static board, converting sacrifice loops, one-shot equipment, and expendable creatures-turned-artifacts into a slow tide of colorless mana. Left alone, it grinds toward an obscene artifact mana base one death trigger at a time.