In-depth technical SEO analysis and SEO on-page testing tool for websites optimization
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
SEOquake - SEOquake provides a browser extension to conduct on-page SEO audit.
SEO PowerSuite - Get all SEO tools in one pack - download free edition of SEO PowerSuite and get top 10 rankings for your site on Google and other search engines!
Lumar - (Previously DeepCrawl) Hosted SEO spider to analyze and find problems with websites.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.