Hey, Rockheads!
Cool news if not necessarily big news, we've just activated Steam Trading Cards! There are nine (9) total cards for players to collect.
If you've already played a bunch of GRIME, you should have a handful sitting in your inventory ready to be traded as you see fit! If you'd like to trade cards around with others to try and complete sets for cool rewards, might I recommend heading on down to the trading sub-forum? I'd also recommend just taking a second and enjoying the beautiful 3D art for each of the trading cards.
Happy hunting!