Solid Explorer - Solid Explorer is a powerful Android file manager featuring access to most popular cloud storages, root access and easy extensibility.
dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
Amaze File Manager - Free and open-source Android file manager with no ads.
AllDup - AllDup is a freeware tool for searching and removing file duplicates on your Windows computer.
Total Commander - A Shareware file manager for Windows® 95/98/ME/NT/2000/XP/Vista/7, and Windows® 3.1.
Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.