Here are the top 10 free online SEO courses:

1. Google SEO Fundamentals (Coursera/University Of California, Davis) This course is a great introduction to the basics of SEO, covering topics like keyword research, on-page SEO, and off-page SEO. It is taught by experts from the University of California, Davis, and is a great way to get started with SEO.
2. SEO Training Course: Learn How to Get Organic Traffic from Search (Ahrefs) This course from Ahrefs is a comprehensive introduction to SEO, covering everything from keyword research to link building. It is taught by Brian Dean, one of the leading SEO experts in the world.
3. Yoast’s Free SEO Training for Beginners This course from Yoast is a great introduction to SEO for beginners. It covers the basics of SEO in a clear and concise way.
4. SEO Training for Beginners (Shopify) This course from Shopify is a great introduction to SEO for businesses that use Shopify. It covers the basics of SEO and how to implement SEO best practices on a Shopify store.
5. On-Page And Technical SEO Course (Semrush) This course from Semrush is a comprehensive introduction to on-page and technical SEO. It covers topics like keyword research, title tags, meta descriptions, and site structure.
6. Intro To Search Engine Optimization (WordPress) This course from WordPress is a great introduction to SEO for WordPress websites. It covers topics like keyword research, title tags, meta descriptions, and plugins.
7. SEO Basics (Conductor) This course from Conductor is a great introduction to SEO for beginners. It covers the basics of SEO in a clear and concise way.
8. A Beginner’s Guide To Local SEO (BrightLocal) This course from BrightLocal is a great introduction to local SEO. It covers topics like local keyword research, citations, and Google My Business.
9. Technical SEO Crash Course with Brian Dean (Semrush) This course from Semrush is a great introduction to technical SEO. It covers topics like crawling, indexing, and website structure.

SEO Essentials Certification (Moz) This course from Moz is a great way to get certified in SEO. It covers the basics of SEO and how to implement SEO best practices.