GitHub Repository Size - Browser extension to show file and repo size in GitHub
RegExr - RegExr.com is an online tool to learn, build, and test Regular Expressions.
Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
rubular - A ruby based regular expression editor
GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
RegEx Generator - RegEx Generator is a simple-to-use application that comes with the brilliance of intuitive regex and is also helping you out to test the regex.