When I first started buying/downloading SVG files, They were just half way saved on my computer I would have to search to find what I wanted and sometimes didn't even know what I had. After I purchased my Black Cat Cougar. I knew I had to get organized. So I printed images of all the files I had saved on my computer. I pasted about 10 images on 1 sheet of paper. Then I cut each image to fit inside each sleeve. I wrote the name of the company I purchase or downloaded the file from. I also labeled dividers for different themes of files I had.
Finally I saved all my files on my computer as SVGCOMPANYINITALSTITLE.SVG this way when I pick out the file I want, I know who designed it and I can go straight to it. Hope this helps. :) Oh and don't forget to back them up on a flash drive as well.