Powerphotos - PowerPhotos lets you organize your Photos libraries on the Mac. You can split a library into smaller ones, merge libraries together, find duplicate photos, and more.

VisiPics - VisiPics does more than just look for identical files, it goes beyond checksums to look for similar...

CleanMyPhone - iPhone Cleaner is designed to free up storage space on iOS devices by removing junk files and Documents & Data, other data etc.

dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.

Czkawka - Multi functional app to find duplicates, empty folders, similar images etc.

Pixiple - Find images similar in pixel and/or metadata content