Pixpie - Optimize your images and speed up your site on WordPress
Smaller - Make your websites load faster
Imagify - Optimize and resize images online and through your CMS.
Website Grader - Grade your website's strengths and weaknesses in seconds.
OptimizeWP - WordPress speed optimization and maintenance service
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.