Tools
This category collects "accessibility tools" – for assessing and testing, but also for creating more accessible experiences.
Low-threshold browser tools
Often, it does not take a full-grown testing suite to find the most critical a11y issues on a web page. Lightweight browser tools allow for a quick assessment.
This CSS file intends to warn developers about possible risks and mistakes that exist in HTML code. It can also be used to roughly evaluate a site's quality by simply including it as an external stylesheet.
Bookmarklets
An Accessibility Bookmarklet for Testing 200% Text Size
This bookmarklet can help you visually check how well a webpage handles text being resized to 200% of the base/default size. It can also help you test for loss of content when checking compliance for WCAG 2.2 Success Criterion 1.4.10 Reflow.
Checklists and cheat sheets
Accessibility checklist - MagentaA11y
How to Meet WCAG (Quickref Reference)
This quick reference to the WCAG 2.1 standard is a handy tool for quickly looking up requirements for specific web design tasks:
A customizable quick reference to Web Content Accessibility Guidelines (WCAG) 2 requirements (success criteria) and techniques.
Announcing the Accessibility Not-Checklist
WebAIM: HTML Semantics and Accessibility Cheat Sheet
In all its brevity, this cheatsheet is a handy little tool for a quick cross-check of HTML code, in particular as learning material for people who are new to working with HTML.
See also
The various specific topics in this Resources category have plenty of tools linked from each of them.