Gitscout - A beautiful Github Issues experience for macOS
Mighty Networks - Mighty Networks enables entrepreneurs, organizations, and companies to create and grow a community-powered brand.
GitHub Reader - A quick way to browse GitHub issues and pull requests.
Nabble - Nabble is a forum software that are embeddable and fully customizable with scripting language.
Codetree - You can manage your entire development process through GitHub.
Bigtent - BigTent is a web-based organization and communication portal for groups.