GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
ForkHub - GitHub client for Android based on the abandoned official app
SourceTree - Mac and Windows client for Mercurial and Git.
GITK - The GITK - Generalized Interface Tool Kit is a set of libraries, which form a (user) interface...
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.
Sublime Merge - Fast git client with integrated merge tool from the makers of Sublime Text