Siteimprove - Consider the Siteimprove Intelligence Platform the newest member of your team.
Website Speed Ranker - Compare how fast your website loads vs your competitors
Sitebeam - Spelling mistakes, SEO, load speed, social media, code, W3C, accessibility & more in one tool.
Website Grader - Grade your website's strengths and weaknesses in seconds.
Ryte - Ryte is a web-based software invented for technical optimization for search engines and improvement of websites.
PageSpeed Ninja - One-click page speed boost for WordPress