Generous Plunderer is a mythic Creature — Human Rogue card from The Big Score Promos (PBIG), collector number 11p. Current market price: $17.39 (foil $15.80), TCGplayer market prices via Scryfall.
Menace At the beginning of your upkeep, you may create a Treasure token. When you do, target opponent creates a tapped Treasure token. Whenever this creature attacks, it deals damage to defending player equal to the number of artifacts they control.