Treasure Keeper is a uncommon Artifact Creature — Construct card from Commander Legends: Battle for Baldur's Gate (CLB), collector number 341. Current market price: $0.24 (foil $0.31), TCGplayer market prices via Scryfall.
When this creature dies, reveal cards from the top of your library until you reveal a nonland card with mana value 3 or less. You may cast that card without paying its mana cost. Put all revealed cards not cast this way on the bottom of your library in a random order.
All Commander Legends: Battle for Baldur's Gate cards and prices