GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
SourceTree - Mac and Windows client for Mercurial and Git.
Gerrit Code Review - OpenSource Git Code Review Tool
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.
Phabricator - Phacility - Phabricator