Useful Patterns

Two-color focus indicator to ensure sufficient contrast with all components
https://www.w3.org/WAI/WCAG21/Techniques/css/C40

Best semantic markup for a Blockquote:
https://coderwall.com/p/tvkd9w/best-semantic-markup-for-a-blockquote

Visually hidden css:
https://a11yproject.com/posts/how-to-hide-content/

Great accordion pattern (but maybe put the heading tag in the section tag):
https://www.aditus.io/patterns/accordion

Sortable tables (and some general approaches to making controls accessible):
https://adrianroselli.com/2021/04/sortable-table-columns.html#ScreenReaders