Hello Bollehopp :) and thanks for noticing !
Indeed, there are too much files in the /rpgmaker folder. It's due to my production script that automatically split the atlas_48x.png file into 768x768 tilesets. The atlas is so long that if produces too many tilesets !
Don't worry, those tilesets (F and G) are empty and not usefull. You can import B to E with no issues :). I'll fix that in the future if I don't add more tiles.
Have a good day !