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.
Website Checker Tech - WebsiteChecker.Tech is SaaS tool that detects SEO and availability issues of your website, making it easier for you to fix them.
SEOquake - SEOquake provides a browser extension to conduct on-page SEO audit.
Netpeak Spider - A desktop tool for fast and comprehensive technical audit of the entire website.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.