Gitscout - A beautiful Github Issues experience for macOS
Xmind - Xmind is a brainstorming and mind mapping application.
GitHub Reader - A quick way to browse GitHub issues and pull requests.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Branches - App for managing issues for your GitHub, GitLab or Bitbucket
FeatureMap - FeatureMap story mapping, simple and effective realtime collaboration and collective intelligence tool.