dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.
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.
FSlint - FSlint is a utility to find and clean various forms of lint on a filesystem. I.E.
Duplicate & Same Files Searcher - Duplicate & Same Files Searcher for Windows 2000 / XP / Server 2003 / Vista / Server 2008 / Windows 7 / Windows 8