Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.
Duplicate File Remover - Duplicate File Remover is a powerful tool to locate (and remove) duplicates on your computer'
AllDup - AllDup is a freeware tool for searching and removing file duplicates on your Windows computer.
dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
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.
Duplicate Photo Cleaner - With this duplicate photo finder you will be able to find duplicate photos and similar images by comparing actual image content.