Apps with 'Find duplicated files' feature
Total Commander-inspired file manager that features two side-by-side panels for navigation.
dupeGuru is a free and open source tool to find duplicate files on your computer. It can scan either filenames or contents.
Full-text morphological search among documents and e-books of dozens of file types, including text in archives and disk images; on the your desktop, LAN, clouds (WebDAV) and removable drives.
UltraFinder is your personal search engine for your PC, network, and remote servers!
Quickly find same or similar pictures/photos including rotated (mirrored) or negative images - duplicates based on content similarity signature.