AptDiff - AptDiff is a visual text / binary files comparison and merging utility for Windows.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
CompareMerge - CompareMerge is a software tool for file comparison and merging text-like files. It is useful for determining what has changed between versions, and then merging changes between...
Online Text Compare - Online Text Compare tool allows you to compare two documents in different formats.
GNU Diff Utilities - GNU Diffutils is a package of several programs related to finding differences between files.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.