OctoDroid - Mobile GitHub client for Android.
SubGit - SubGit is a tool for a smooth, stress-free SVN to Git migration.
GITK - The GITK - Generalized Interface Tool Kit is a set of libraries, which form a (user) interface...
SmartGit - SmartGit is a front-end for the distributed version control system Git and runs on Windows, Mac OS...
Sublime Merge - Fast git client with integrated merge tool from the makers of Sublime Text
SourceTree - Mac and Windows client for Mercurial and Git.