Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2906449.
Remixed Bokix's Nintendo Switch mini Game Card Case to be closer to the aspect ratio of the original cases, mainly so the artwork doesn't have to be distorted to print. I trimmed off ~8mm from the front and back, while maintaining the cartridge holding part as is.
I added a version that has a window to view the label of the game inside in case you don't want to print one. It has walls that just about reach the cartridge to help keep dirt and dust out.
I've found great results for the hinge by laying it flat on the build platform just after printing so it's still warm, and folding the side up while keeping the rest of the cartridge flat. This will help crease the edge of the hinge. Rotate and repeat on the other side. Lastly, once you've creased the edges, it helps to hold it spine edge flat against the bed to flatten it out.
I've uploaded my resized printing template, as well as a PSD template for printing the spine. All you should need to do is edit the text in the textbox.