Free SEO Checker by Spotibo - An SEO checker that analyses based on Google's algorithm 👀
Google Doc Publisher - Make Google Docs good-looking in two clicks
Serpstat Website SEO Checker - Check your website's SEO, analyze competitors and keywords
Content Editor 2.0 by Surfer - Content Editor is the most advanced content optimization tool that allows you to write and grade your work.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
SEO Minion - Chrome extension & Firefox add-on to help you with SEO