dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
Rdfind - Rdfind is a program that finds duplicate files.
FSlint - FSlint is a utility to find and clean various forms of lint on a filesystem. I.E.
Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.
AllDup - AllDup is a freeware tool for searching and removing file duplicates on your Windows computer.
Duplicate Media Finder - Duplicate Media Finder locates and deletes identical files and similar media