There's 2 type of card, The regular Patreon card for $15 dollar supporter, they are the white card that monster occassionally drop, and have a name only.
Then there are the Gold card that are $60(Not aviable currently) which you can see in game as the other NPC with a radio near them(Brown hair agent in stage 1, Elve girl and Manrisa in Stage 2, Dead scientist with wife and Failed agent in Tube in stage 3) They also have gold card near them, which is used to open their dossier, and access to the new stages in 1.5 So it's a reward of a character of your choice(Origional or other) in a situation done in sprite style.
But the quota for that reward is currently full, so you can probabely check after the release of ver 1.5, in december
Then there are the Gold card that are $60(Not aviable currently) which you can see in game as the other NPC with a radio near them(Brown hair agent in stage 1, Elve girl and Manrisa in Stage 2, Dead scientist with wife and Failed agent in Tube in stage 3) They also have gold card near them, which is used to open their dossier, and access to the new stages in 1.5
So it's a reward of a character of your choice(Origional or other) in a situation done in sprite style.
But the quota for that reward is currently full, so you can probabely check after the release of ver 1.5, in december
More info on https://www.patreon.com/Sourjelly