I checked out the links above. Let me make some brief comments about where my program fits in.
Most(all?) of the links from wraith are pretty fancy tools for creating cards for certain games, with images, stats, and lots of text.
My program is purely for laying out large numbers of image files very precisely to fit card stock paper for printing. You can customize the details of the card stock and save templates, so it can be used to print on playing card punch-out paper, or business card paper, etc.
My program has no features for creating nice layouts with text and stats, etc. It's just for taking a large collection of images and laying them out precisely for printing, with a few options for how the images are resized, etc., and then doing the actual printing.
While it has a few extra features, like things to help you align the card stock, you can see that it's focus is very limited.
Note: I also have an older set of open source python utilities for making/prototyping custom playing cards programmatically: https://www.donation...ser/pythonprotocards