Diagnostic.css : Diagnostic.css is a stylesheet which allows the user to test for common errors in a page's markup.
Also : https://github.com/karlgroves/diagnostic.css
webhint : webhint is a linting tool that will help you with your site's accessibility, speed, security and more, by checking your code for best practices and co...
Skipfish : Skipfish is an active web application security reconnaissance tool. It prepares an interactive sitemap for the targeted site by carrying out a recursi...
aXe : Automated tool to find Accessibility defects on your web site by using the aXe Chrome extension. Drop the aXe on your accessibility defects! We believ...
Lighthouse : Lighthouse is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authenti...
Monitor the accessibility of your websites with pa11y-dashboard, and protect against accessibility errors creeping into your codebase.