I had the same problem with my embroidery designs. I've gotten carried away over the years and have way more than I could ever hope to use. I discovered that putting them on the USB meant I had to weed through tons of designs to find the one I wanted so that didn't work too well.
I got a program called Catalog It! First I created folders on my desktop and put my designs in the folders (like Christmas, borders, animals, etc.). In Catalog It! I made folders with the same name, then copied the designs into those folders. When I go into Catalog It! I see the actual design, size, stitch count, colors, it lists the colors for the thread I use (there are several thread categories to choose from), and any notes I made regarding the design and it tells me what folder to look into to download the design onto my USB - or whatever software I'm using.
Catalog It! isn't very expensive and it's really simple to use. It's only used for categorizing, viewing and transferring designs to USB or other software you have for that purpose.