I’ve had great luck printing on cardstock and laminating cards before. They wind up a lot thicker than professionally printed cards, but they are easy to manipulate comfortably. (Depending on the lamination thickness, they might be a bit of a pain to riffle shuffle.) As to format: * For printing, a PDF with like 8 up and cut lines is helpful. * For VTT usage, per-card face image files make import a lot easier.