Ray is a lightweight desktop app that helps you debug your PHP app. You can get a free demo that can be unlocked with a license. You can use Ray in WordPress by manually cloning the repo or installing the plugin via the Plugins section on the WordPress admin UI.

A nice project that will speed up your snippets creation process.

Responsively is An open source tool that lets you inspect a web page on multiple screens. It comes with several very handy features such as the ability to inspect elements, a list of common devices screen size, coaching control, and more.

A Q&A tool for finding answers to your coding questions. Comes also as a site you can browse in, or a handy chrome extension.

A list of recommended, mostly free font suitable for coding. Compiled the awesome guys from css-tricks.com

By Joshua Comeau of www.joshwcomeau.com joshwcomeau.com. Joshua built this project because he was sick of forgetting what these blasted operators are called. Often he'll remember the operator's syntax, but not exactly how it works. One can't use search engines to find out more about them, since they ignore "special characters"!

DevDocs combines multiple API documentations in a fast, organized, and searchable interface. Can also be downloaded as a PWA.