Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.
rubular - A ruby based regular expression editor
BeakerX - Open Source Polyglot Data Science Tool
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.
Observable Notebooks - The portfolio and technical blog of Chris Henrick – provider of professional web development, data visualization, GIS, mapping, & cartography services.
RegExr - RegExr.com is an online tool to learn, build, and test Regular Expressions.