Space Pilgrim Episode III: Delta Pavonis had Steam trading card support added on 4 February 2016. There are 5 cards in the series, and you'll receive 3 cards at random for purchasing and playing the game.
The other installments in the game series--Space Pilgrim Episode I: Alpha Centauri, Space Pilgrim Episode II: Epsilon Indi and Space Pilgrim Episode IV: Sol--also have trading card support.