Koalati - Automated website testing and quality control tools for developers and agencies.
Ahrefs Backlink Checker - With the world's biggest index of live backlinks (over 15 trillion), Ahrefs Backlink Checker will show you the most complete backlink profile for any website.
RankScience - Advanced Content Optimization Software for SEO
Plerdy - Plerdy is a comprehensive conversation rate optimization software that caters to professional online marketers and agencies, allow them to enhance website performance and increase revenue greatly.
WAO - WAO.io offers web analytics and optimization solutions.
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.