GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
SourceTree - Mac and Windows client for Mercurial and Git.
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.
TortoiseGit - TortoiseGit is an easy to use client for the Git distributed revision control system.
Fork - Fast and Friendly Git Client for Mac
git-cola - git-cola is a powerful GUI for git, a distributed revision control system.