So I changed my whole organizing structure last year, and I love it. For templates I have them all organized by number of photos. Not by designer at all. I name them with the pack name and designer name, followed by 1-2-3-4 (so they have different names), and I colour code them on my Mac by store (I tag SSD with purple). Then when I use one I add a z- before it so it naturally moves to the bottom of the folder and I know I've used it.
Main templates folder:
How it looks when I open it (I only keep the Tiff file, it shows the preview in Finder)
And the ones I've used:
