SourceTree - Mac and Windows client for Mercurial and Git.
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.
TortoiseGit - TortoiseGit is an easy to use client for the Git distributed revision control system.
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.
GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
CodeHub - CodeHub is the most complete, unofficial, client for GitHub on the iOS platform.