Mercurial SCM - Mercurial is a free, distributed source control management tool.
Visual Studio Team Services - Visual Studio Team Services (VSTS) provides unlimited Git hosting, cloud build for CI, agile planning and continuous delivery.
Apache Subversion - Mirror of Apache Subversion. Contribute to apache/subversion development by creating an account on GitHub.
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.
Perforce - Self-hosted Version Control Software
GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.