dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
Duplicate File Finder by Nektony - Duplicate File Finder is a Free app to find and remove duplicates on your Mac.
Duplicate Cleaner - Duplicate Cleaner: the fastest and most popular tool for finding duplicate files. Over 1 million downloads: Get your copy now! Free and Pro versions available.
AllDup - AllDup is a freeware tool for searching and removing file duplicates on your Windows computer.
MacPaw Gemini 2 - The intelligent duplicate file finder
Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.