Alacrian Armory is a uncommon Artifact card from Aetherdrift (DFT), collector number 2. Current market price: $0.27 (foil $0.34), TCGplayer market prices via Scryfall.
Creatures you control get +0/+1 and have vigilance. At the beginning of combat on your turn, choose up to one target Mount or Vehicle you control. Until end of turn, that permanent becomes saddled if it's a Mount and becomes an artifact creature if it's a Vehicle.