GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
Git-Repo - Manage Gitlab, GitHub and Bitbucket from the command line
SourceTree - Mac and Windows client for Mercurial and Git.
Gitential - Analytics for Git Repositories
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.
Diff So Fancy - Make Git diffs look good