I wanted a card holder. I had access to a 3D printer, so I looked for designs. I didn't like the design I found though, so the obvious solution was to learn Fusion 360 and make my own.

More than a year of using it after many revisions, here it is.

Thingiverse

Low profile, no supports, and easy to print. PLA is okay: the one I've been using for over a year is PLA and just fine. A different material would probably be better, but I couldn't print with others.