Joycon grip which holds 4 game cartridges.
I have had the best results printing this part upright. The tolerances of the grip rails are pretty tight. It's best to incrementally sand down the outside faces of each rail and clean out the inner rails until the joycons slide in smoothly.
Additionally, the little nubs which keeps each cartridge in place may need a pass or two with some sand paper to make pushing the carts out easier.