With over 5 million active installations, Yoast SEO is the most popular SEO plugin since 2008. They have premium add-ons called Local SEO, Video SEO, News SEO, and WooCommerce SEO to further improve the SEO of your WordPress site.

All-in-One SEO is also a popular WordPress SEO plugin with more than 3 million active installations. But if you are looking for only the free version, Yoast and Rank Math’s free version is better than this.

SEO Press is a simple, user-friendly, and flexible WordPress SEO plugin and you can integrate it with many popular 3rd-party apps like Google Analytics.

Rank Math is a fully completed SEO solution for WordPress and it seems like this plugin is the biggest(features-wise) SEO plugin in the market.