Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Beyond Compare - Beyond Compare allows you to compare files and folders.
DirEqual - Compare and Sync Mac and Windows folders with DirEqual
Diff Checker - Diff Checker is a free online diff tool that quickly and easily gives you the text differences...
AptDiff - AptDiff is a visual text / binary files comparison and merging utility for Windows.