SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Free SEO Checker by Spotibo - An SEO checker that analyses based on Google's algorithm 👀
Rank Tracker - Rank Tracker is an SEO tool for tracking and improving keyword rankings across multiple websites and search engines.
SEO Analyzer By Neil Patel - A free SEO analyzer for your site
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
SEO Minion - Chrome extension & Firefox add-on to help you with SEO