Bugsee - See video, network & logs leading up to bugs or crashes
Smaller - Make your websites load faster
Buglife - Seriously awesome bug reporting for iOS apps
Website Grader - Grade your website's strengths and weaknesses in seconds.
Instabug - The top apps in the world rely on Instabug for beta testing, user engagement and crash reporting.
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.