SEO Analyzer By Neil Patel - A free SEO analyzer for your site
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Serpstat Website SEO Checker - Check your website's SEO, analyze competitors and keywords
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters