Inspired by Bob from I Like to Make Stuff's video (
https://youtu.be/Z8YSEOXOpN4), here is a complete two-piece set for a Nintendo Switch game storage controller. Like the controller Bob made, the tray can hold up to six cartridges. The base has a picture of the Nintendo Switch logo etched on the front.
Special thanks to Bob for the JoyCon rails. For the product, said rails have been modified so you don't have to nail them to the controller.