The most common Wordpress plugins are:
5.wordpress SEO by Yoast
SEO Plugins comes with some useful built-in functionalities for optimizing your site, including meta tags, neat and tidy navigation links, and optimized permalinks. They fix you website XML sitemap, robots.txt, Onpage content analysis, overall settings and configurations.
The most popular SEO plugins used by almost all SEO agencies are -
1. All in One SEO Pack - All in One SEO Pack was created in 2007 by Michael Torbert and Steve Mortiboy. All in One SEO Pack, has all the settings on a single page whcuh makes it easy to use for most of the SEOs/Webmasters.
2. WordPress SEO by Yoast - Yoast SEO, started out as WordPress SEO by Yoast in 2010. Yoast Seo is an awesome SEO plugin. Over the past 4 years, it took over the All In One Seo Pack. There are some elements that make Yoast Seo complicated to use it and does not have all the skills of All in One Seo Pack. One of the advantage of Yoast SEO is it comes with a powerful content analysis tool that helps you optimize every single post or page on your website.
Yoast SEO is the most popular plugin used by everyone .