They Came From The Moon was a supported title that has since been removed from the Steam Store.
They Came From The Moon was released on Steam with trading card support on 6 January 2016, and there are 9 cards in the series. The game has since been removed from the Steam Store, and no items can be bought or sold on the Community Market.
Trading Cards
Foil Cards
Badges
Booster Pack
Emoticons
Profile Backgrounds