Possible to filter/search for non-Steam games in Steam Library?

Hey all!
Since the new Steam library dropped, I've been spending time organizing my library and adding artwork to games missing it. I have a pretty large library and it's a bit hard to locate things if I'm not on top of it. One thing I'd like to do is find all of the non-Steam games I have added to the library over time. I can't seem to find a way to search or filter for these in Steam. Does anyone know how I might find them? Ideas/suggestions?

Moving forward, I'm going to keep them organized in a non-Steam collection and possibly by launcher.

Thanks!