Narfi, Betrayer King is a uncommon Legendary Snow Creature — Zombie Wizard card from Kaldheim (KHM), collector number 224. Current market price: $0.27 (foil $0.31), TCGplayer market prices via Scryfall.
Other snow and Zombie creatures you control get +1/+1. {S}{S}{S}: Return this card from your graveyard to the battlefield tapped. ({S} can be paid with one mana from a snow source.)