Total Commander - A Shareware file manager for Windows® 95/98/ME/NT/2000/XP/Vista/7, and Windows® 3.1.
dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
fman - An unexpected gift. January 07, 2018 by Michael. One of the nice things that happened last week was an fman user writing in to say that 1) fman "is THE BEST SOFTWARE" (sic). And that 2) he would like to send me a $50 tip.
AllDup - AllDup is a freeware tool for searching and removing file duplicates on your Windows computer.
Solid Explorer - Solid Explorer is a powerful Android file manager featuring access to most popular cloud storages, root access and easy extensibility.
Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.