There are many of these type of enhancements for old 8-bit computers as well. I'm most familiar with the Commodore 64 and have purchased a couple over the years. One is a cable that will allow you to transfer data to and from a Commodore 64 disk drive or use a DOS based computer as a hard drive. I also have an adapter that allows you to use SD cards as storage.
Back when I had an original PlayStation I also used to have an adapter that would allow you to play backup and import games on it.
Very cool mods you are mentioning there. Those SD card cartridges are big on consoles such as #Sega #Genesis, Super #Nintendo and others.