"Missing Alt Text" Filter in the Media Library
Adds a dropdown to the Media Library list view that shows only images without alternative text, so you can fix them one by one.
Snippet Library
Accessibility snippets for WordPress
Snippets that make WordPress easier for everyone to use: skip links, focus styles, better link text and fixes for common accessibility issues. For site owners who want a site that works with keyboards and screen readers.
Alt Text Editor for Images Missing a Description
Adds Media > Alt Text Editor, a page that lists images without alternative text with a thumbnail and a text field next to each, so you can describe dozens of images quickly and save them all at once.
Highlight Empty Alt Text Fields in the Media Modal
Outlines the Alternative Text field in red when it is empty in the media library and media modal, so authors notice it before inserting an image.