RobinGupta Bulk Domain Authority Checker - Free tool to bulk check domain authority, Page Authority, Spam score & IP Address.
Seolyzer - Seolyzer is the ultimate SEO tool that provides you with all the information you need to improve your website’s health and performance.
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.
SEOmator - SEO website analysis & audit 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.
Whatsmyserp - Powerful Rank & Serp Tracking. Completely Free.