Appsero - Appsero is a killer WordPress Analytics, Licensing & Deployment Tool. Appsero is the perfect companion for WordPress plugin & theme developers.
SEO Analyzer By Neil Patel - A free SEO analyzer for your site
Squirrly SEO Focus Pages - Waze for navigating Google Ranking factors
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
Freemius - Freemius is a suite of solutions for monetization, analytics, and marketing automation for freemium and premium WordPress plugins.
Serpstat Website SEO Checker - Check your website's SEO, analyze competitors and keywords