I have my digi supplies organized by the store name, then in a folder for each designer. Within that designer folder I keep new kits loose and have a separate folder for the ones I've used. That way, I immediately see which kits I have yet to scrap with. I also keep freebie products in their own folder within the designers folder. Store collabs and things like that are kept in the main folder for the store.
I have also found that deleting frequently helps with my organization. About 4x a year I go through my folders and clean out.
