Unclaimed Territory is a uncommon Land card from Ixalan (XLN), collector number 258. Current market price: $0.37 (foil $1.27), TCGplayer market prices via Scryfall.
As this land enters, choose a creature type. {T}: Add {C}. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.