I was reading WCAG's accessibility success criteria pages and the OWASP cheat sheets and they both ar e something that one needs to read through atleast once.
What are some other documents that are a must-read?
WCAG and OWASP indicate web development, probably front-end development.
You will want to learn the standard DOM methods. Walking the DOM as a tree structure as opposed to treating it as a database to query will increase your application capabilities. Learning to access the DOM without parsing a selector string will make your application many thousands of this new faster.
I maintain my own guide of concise webdev tips that's mostly distill from and links to recommendations from OWASP, Mozilla and Google which you might find a good jumping-off point: https://www.checkbot.io/guide/
