Here is a flash cart for a system that does not get that much attention. This is for the Nintendo Virtual Boy.
This is a standard Virtual Boy cartridge with a mini USB port on it. This is for writing roms to the 16 MBits (2 MBytes) internal flash memory. The down side is, it only holds one game at a time. This is a bit of a let down since I am so used to the Everdrives carts which are some sort of SD/microSD and can hold a whole library. To load a game to the Flashboy + you will need to use the supplied loader software and connect the mini USB cable to your PC. This is a pretty simple & straight forward task.
The cart does not have a backup battery so games like Galactic Pinball and VB Wario Land are playable, but can not take advantage of the battery.
Normally I open up the carts to take pictures of but I am not wanting to break the superglue that holds this 3D printed case together. I will will pop it open in the future and update this post.