"If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason." -Jack Handey
FFP is more aggressive than most companies about stopping stuff like that. Early on, people were trading images of cards they made for town items, for example (which don't even have proper cards in the game), and FFP shut it down.
You can find card maker tools out there, but not usually any pre-made cards with game text on them.