SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
SEOmator - SEO website analysis & audit tool
Lumar - (Previously DeepCrawl) Hosted SEO spider to analyze and find problems with websites.
SEOquake - SEOquake provides a browser extension to conduct on-page SEO audit.
Marketing Miner - SEO tool for data-driven marketers
Screaming Frog - Screaming Frog is search engine marketing agency offering search engine optimisation and pay-per-click advertising services.