Beyond Compare - Beyond Compare allows you to compare files and folders.
Link Shell Extension - Link Shell Extension (LSE) provides for the creation of Hardlinks , Junctions , Volume Mountpoints...
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Symlink Creator - Symbolic Link Creator. GUI for mklink (Microsoft Windows symlink utility).
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.
FileMenu Tools - FileMenu Tools lets you customize the context (right-click) menu of Windows Explorer.