Re Upload from my thingiverse https://www.thingiverse.com/thing:4733946/files

NOTE: Not all cartridges are built with the same width… do not force the cartridge. I noticed this when I was testing different games in the same printed NES cartridge holder and saw that some games can fit just right or even a bit loose and also a bit tight.

1/27/2021
I'm adding a version with an opening in the back to help remove the cartridge with ease. I did not come up with this idea, Credit to FlyingHellfish on Thingiverse here's a link to their profile https://www.thingiverse.com/flyinghellfish/designs