WinMerge - WinMerge is an open source differencing and merging tool for Windows.
kdiff3 - KDiff3 is a file and directory diff and merge tool which compares and merges two or three text...
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.
Beyond Compare - Beyond Compare allows you to compare files and folders.
AptDiff - AptDiff is a visual text / binary files comparison and merging utility for Windows.
Tkdiff - tkdiff is a graphical diff viewer based on the Tk framework.