Find duplicate files.
dupeGuru, dupeGuru Music Edition, and dupeGuru Pictures Edition. The music and pictures editions are specialized for finding similar music files and pictures. For example, the music edition will find the same song, even if they’re in different MP3 files encoded at different bitrates. Or the pictures edition will find copies of the same photo even if they’ve been resized, rotated, or slightly edited. This utility uses a “fuzzy match” algorithm and can find files that are very similar and not just completely identical.
Duplicate File Finder