Beyond Compare - Beyond Compare allows you to compare files and folders.
kdiff3 - KDiff3 is a file and directory diff and merge tool which compares and merges two or three text...
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.
P4Merge - A valuable tool for diagnosing continuous integration bugs, Folder Diff also measures how much code must be resolved in pending merge scenarios. Visually compare two versions using image diff within P4Merge to determine changes made.
Tkdiff - tkdiff is a graphical diff viewer based on the Tk framework.