A-Urza, Powerstone Prodigy

The digital rebalance is a single, surgical change: the body dropped from three mana to two, while the token trigger stayed exactly as it was in paper. That one-mana discount is what turns a slow value creature into a durable two-drop, a 1/3 that shrugs off most of the damage-based removal that would otherwise clip it while it digs. The looting ability (pay a mana, tap, draw a card, then discard one) is a filtering engine that reads for artifacts. Feed one expendable artifact into each loot and you convert unwanted cards into tapped mana rocks, one per turn cycle. Two clauses govern that conversion, and they do different jobs. The "one or more artifact cards" phrasing means a single discard event yields exactly one Powerstone no matter how many artifacts leave your hand at once; you cannot spike a mass-discard into a pile of tokens. The separate "only once each turn" clamp prevents multiple discard events in the same turn from each triggering, so effects layered on top of the loot cannot stack tokens across a turn. The Powerstone is the deeper balancing pressure: its colorless mana funds artifacts and activated abilities but never a nonartifact spell, walling the ramp inside the artifact shell. The trigger also cares about the exit: the artifact must leave hand by discard, not by sacrifice or destruction, so it rewards a hand stocked with cheap castoffs rather than a graveyard full of them.