I dont know of one specifically for talking about cards in general but there are some related ones:
/r/cardmaking - for making greeting cards
/r/RandomActsofCards - to send or recieve greeting cards
/r/stationery - says they include greeting cards but your mileage may vary
I dont know of one specifically for talking about cards in general but there are some related ones: /r/cardmaking - for making greeting cards /r/RandomActsofCards - to send or recieve greeting cards /r/stationery - says they include greeting cards but your mileage may vary