Curator's Ward is a uncommon Enchantment — Aura card from Dominaria (DOM), collector number 49. Current market price: $0.36 (foil $2.87), TCGplayer market prices via Scryfall.
Enchant permanent Enchanted permanent has hexproof. When enchanted permanent leaves the battlefield, if it was historic, draw two cards. (Artifacts, legendaries, and Sagas are historic.)