For now we are going to stick with these 3 options: - Fronts only cards. - Print the "Fronts only" file, and the "backs only" file on the same sheet to get cards with front and back. - Foldable (front and back on the same face, cut and fold to get a thicker card with front and back).
Have you thought about perhaps offering the game through DriveThruCards or The Game Crafter? That way printing costs could be deferred and fans could pick up high-quality printed copies more easily. I ask only as I don't know if Itch.io offers PoD as of now.
