Curse of Unbinding is a rare Enchantment — Aura Curse card from Midnight Hunt Commander (MIC), collector number 50. Current market price: $2.02, TCGplayer market prices via Scryfall.
Enchant player At the beginning of enchanted player's upkeep, that player reveals cards from the top of their library until they reveal a creature card. Put that card onto the battlefield under your control. That player puts the rest of the revealed cards into their graveyard.