Swindler's Scheme is a rare Enchantment card from New Capenna Commander (NCC), collector number 96. Current market price: $0.34 (foil $0.18), TCGplayer market prices via Scryfall.
Whenever an opponent casts a spell from their hand, you may reveal the top card of your library. If it shares a card type with that spell, counter that spell and that opponent may cast the revealed card without paying its mana cost.