Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
devmarks.io - Bookmarking for Developers
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
GitHub Repository Size - Browser extension to show file and repo size in GitHub
Board for Github - A webview based GitHub project app with native features
Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.