RankScience - Advanced Content Optimization Software for SEO
Website Grader - Grade your website's strengths and weaknesses in seconds.
Irayo - Irayo is an intent-based SEO analysis and optimization tool.
Checkbot - Checkbot will boost the SEO, speed and security of your site by checking you're following 50+ web best practices. Browser extension with free and paid plans.
Siteimprove - Consider the Siteimprove Intelligence Platform the newest member of your team.
PageSpeed Ninja - One-click page speed boost for WordPress