Figured it out. There's a setting for hiding preinstalled roms. Enable that and all those systems will vanish.

@olivierdroid92 See my OP. I did that. There are no roms in the folder. It still shows up.

I realize this has been asked a million times, but everything I've found on the topic doesn't match what I have. Some info about my setup:

Version 8.0-electron
Connecting to my system with both windows exporer and putty.

Most solutions state to just delete the roms in the folder, however, I never put any roms in the folder, it's what came preloaded on the system, but when I go into the folder using windows explorer, there's already nothing in the folder except a handful of readme documents. There are already no roms in the folder as far as I can tell. I have hidden items enabled and nada, yet the systems and preloaded roms still show up in Recalbox.

I tried creating a folder called unused and just cutting and pasting the systems I didn't want into that folder, but upon reboot it just put all the folders back, only this time completely empty, and yet they still show up. I'm not sure what I'm missing here.