GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
Google Open Source - All of Googles open source projects under a single umbrella
Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
SmallDevTools - Handy developer tools with a delightful interface
GitHub Hovercard - GitHub Hovercard provides neat hovercards for GitHub.
whatdevsneed - This is whatdevsneed.