Fixlight
Accessibility fixes, not an accessibility widget.
Fixlight is a free WordPress plugin that finds accessibility problems on your site and fixes the safe ones in your site's own HTML: page language, skip links, keyboard focus, form labels, icon buttons, image alt text and more. It adds no toolbar and no script for your visitors, needs no account, and has no page limits.
It also shows you, in plain language, what still needs a person, and why it matters.
Fixlight helps make a site more accessible. No plugin can make a site fully accessible or compliant with a law on its own, and Fixlight never claims to.