Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
CopyCoding - Machine learning and data science online community
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
Betterer - Improve your codebase, incrementally
Board for Github - A webview based GitHub project app with native features
CodeKeep - Codekeep lets you store and share bits of code and text with other users. Snippets can be organized into folders/labels for instant reuse.