WPMU DEV - WPMU offers WordPress Plugins, WordPress Themes, WordPress Multisite and BuddyPress Plugins and Themes.
XAMPP - XAMPP is a free and open-source cross-platform web server that is primarily used when locally developing web applications.
Firefox Developer Edition - Built for those who build the Web. The only browser made for developers.
MAMP - MAMP is the abbreviation for Macintosh, Apache, MySQL, and PHP. It is a reliable application with its four components that allows you to access the local PHP server as well as the database server (SQL).
AMPPS - MAMP and WAMP stack with Latest PHP, Apache, MySQL and Softaculous. Install and manage apps like PHP, WordPress and much more with just one click.
.NET - .NET is a free, cross-platform, open source developer platform for building many different types of applications.