These stackable storage shelves will fit Super Nintendo (SNES) cartridges.
There is a 1x4, 1x2, and 1x1 version. They're all the same width, so you can mix and match if you want.
The tolerances on the feet/connector aren't super-tight, so they should fit together fine. I've printed a set at .38 and they went together fine (with just a little coaxing).