Riot : Riot allows teams to communicate across a wide range of collaboration apps. If some team members use Riot while others use IRC, Slack or Gitter, Riot ...
Zulip : Powerful slack-like open source group chat
Beanstalk : Code hosting for private teams.
Imagine a single process to commit code, review with the team, and deploy the final result to your customers.
Commento : A lightweight, open source, tracking-free comment engine alternative to Disqus.
GitLab is a web-based Git repository manager with wiki and issue tracking features. GitLab offers hosted accounts similar to GitHub, but also allows its software to be used on third party servers.