GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
Epic Pen - A windows tool for drawing over your desktop and applications
SourceTree - Mac and Windows client for Mercurial and Git.
gInk - An on-screen on-screen annotation software for Windows.
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.
Gromit-MPX - Create annotations by directly drawing on your screen.