I'm not sure I know exactly what you mean so I thought I'd ask.

1. Does such a list exist? (updated to work in current gimp, or a complete filter list for any version?)
2. Screenshots of filter effects?
3. How many filters have a Reference Manual?

Either way, seeing these made me think of one really big wish.
A truly comprehensive and maintained filter/plugin website/repository that is integrated into gimp, complete with examples/screenshots you could browse, Keyword search, and notes on each. (Last working version, active/abandoned, ratings, etc...) Kinda like jedit plugin manager but with screenshots.

It could check for updates and also give options as to where you would like the filter to live in the menu as well as a place to set the default values. Going far out on this limb, it could also have a built in simple text editor to look at an make changes to the script in real time.

If you're gonna wish, wish big!

P.S. Rod. I am blown away by your sig picture. Is there a link to a full size image?