dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
Pixiple - Find images similar in pixel and/or metadata content
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 Media Finder - Duplicate Media Finder locates and deletes identical files and similar media
Visual Similarity Duplicate Image Finder - Visual Similarity Duplicate Image Finder will find similar and duplicate photos. Organize photos easily - supports 300+ Image Formats Including RAW.
AllDup - AllDup is a freeware tool for searching and removing file duplicates on your Windows computer.