I use a File Explorer replacement called xplorer2 from Zabkat. It has a simple (primitive?) duplicate checker. You can find a link to a Youtube demo on
this page (it's about halfway down). It's not a feature I had used until just now. There's not much control of the filtering, but there is a lot you can do with the results of your search.
It may not be a good match ... but it can run in portable mode which I find useful for programs you don't use that often.
Offered FWIW