rubular - A ruby based regular expression editor

RegExr - RegExr.com is an online tool to learn, build, and test Regular Expressions.

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.

Reggy - Signup forms filled automatically with random identities

Expresso - The award-winning Expresso editor is equally suitable as a teaching tool for the beginning user of regular expressions or as a full-featured development environment for the experienced programmer with an extensive knowledge of regular expressions.

Regex Widget - Regex Widget is a lightweight, easy-to-use regular expression tester released under the LGPL license.