BackstopJS : BackstopJS automates visual regression testing of your responsive web UI by comparing DOM screenshots over time.
Greasemonkey : Greasemonkey is a Firefox extension that allows you to customize the way webpages look and function.
Squoosh : Squoosh is an image compression web app that allows you to dive into the advanced options provided by various image compressors.
Skipfish : Skipfish is an active web application security reconnaissance tool. It prepares an interactive sitemap for the targeted site by carrying out a recursi...
The Web Developer extension adds various web developer tools to a browser. The extension is available for Chrome, Firefox and Opera, and will run on any platform that these browsers support including Windows, OS X and Linux.