Dragon Throne of Tarkir is a rare Legendary Artifact — Equipment card from The List (PLST), collector number KTK-219. Current market price: $1.69, TCGplayer market prices via Scryfall.
Equipped creature has defender and "{2}, {T}: Other creatures you control gain trample and get +X/+X until end of turn, where X is this creature's power." Equip {3}