Gitea - A painless self-hosted Git service
Xmind - Xmind is a brainstorming and mind mapping application.
GitBucket - GitBucket is the easily installable open-source GitHub clone written with Scala.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.