Thanks Jerry, very helpful! I just added two of them which were new to me.
As an author of neurodiverse (ADHD) fantasy, I find accessibility crucial, and use "Siteimprove Accessibility Checker" to help me find accessibility issues in my website or landing pages, and "Read Aloud: A Text to Speech Voice Reader" for the same reason - to detect problems in my designs. Of course, fixing issues still may require a lot of work, but these help me learn at least what still needs to be done... :-)
Links:
1. https://chrome.google.com/webstore/detail/siteimprove-accessibility/djcglbmbegflehmbfleechkjhmedcopn
2. https://chrome.google.com/webstore/detail/read-aloud-a-text-to-spee/hdhinadidafjejdhmfkjgnolgimiaplp