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.

Ahrefs - Ahrefs is a toolset for SEO and marketing. We have tools for backlink research, organic traffic research, keyword research, content marketing & more. Give Ahrefs a try!

SpyFu - SpyFu helps companies determine where the company needs to go and how to get there. Improve experience with clients by watching trends and planning new strategies.

SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters

Searchmetrics - Searchmetrics Suite for enterprise companies provides SEO marketing and analytics, SEO optimization, social and content marketing.