Solid Explorer - Solid Explorer is a powerful Android file manager featuring access to most popular cloud storages, root access and easy extensibility.
Beyond Compare - Beyond Compare allows you to compare files and folders.
Amaze File Manager - Free and open-source Android file manager with no ads.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Total Commander - A Shareware file manager for Windows® 95/98/ME/NT/2000/XP/Vista/7, and Windows® 3.1.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.