Goat Simulator had Steam trading card support added on March 28, 2014. There are 5 cards in the series, 3 of which you'll receive for purchasing and playing the game.
Trading Cards
Foil Cards
Badges
Level 1
Phallic Corn
Phallic Corn
Level 2
Erect Banana
Erect Banana
Level 3
Hard Aubergine
Hard Aubergine
Level 4
Throbbing Chilipepper
Throbbing Chilipepper
Level 5
Tallywhacker Carrot
Tallywhacker Carrot
Foil Badge
Tasty Carrot
Tasty Carrot
Kuchen
Emoticons
Profile Backgrounds