tota11y - An accessibility visualization toolkit from Khan Academy
Monitor Backlinks - Easy Link Management - SEO Tool for automatically checking your backlinks.
Nibbler - Free tool for testing how good your website is, and what you can do to improve it. Check accessibility, SEO, social media, compliance and more.
Backlinks by Neil Patel - A backlinks research tool for competitive intelligence
Page Speaker - Modern web accessibility tools for agencies & webmasters
Botify - Traffic Managers, SEO Managers, Webmasters:Crawl your site to extract all of its metadata and identify areas for improvement