Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
Gitstalk - Discover what your favorite GitHub users are up to
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
CodeMyUI - Handpicked code snippets you can use in your web projects
GitHub Hovercard - GitHub Hovercard provides neat hovercards for GitHub.
Dyllo - A clean and simple way to view a Github user's information