Untethered Express is a uncommon Artifact — Vehicle card from Aether Revolt (AER), collector number 179. Current market price: $0.24 (foil $0.85), TCGplayer market prices via Scryfall.
Trample Whenever this Vehicle attacks, put a +1/+1 counter on it. Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)