The first true all-in-one SEO solution for WordPress, including on-page content analysis, XML sitemaps and much more.
Plugin link: https://wordpress.org/plugins/wordpress-seo/
W3 Total Cache
The highest rated and most complete WordPress performance plugin. Dramatically improve the speed and user experience of your site. Add browser, page, object and database caching as well as minify and content delivery network (CDN) to WordPress.
Plugin link: https://wordpress.org/plugins/w3-total-cache/
Reduce image file sizes, improve performance and boost your SEO using the free free WPMU DEV WordPress Smush API.
Plugin URL: https://wordpress.org/plugins/wp-smushit/
Google XML Sitemaps
This plugin improves SEO using sitemaps for best indexation by search engines like Google, Bing, Yahoo and others.
Plugin URL: https://wordpress.org/plugins/google-sitemap-generator/
Post Views Counter
Post Views Counter allows you to display how many times a post, page or custom post type had been viewed in a simple, fast and reliable way.
Plugin URL: https://wordpress.org/plugins/post-views-counter/
Used by millions, Akismet is quite possibly the best way in the world to protect your blog from spam. It keeps your site protected even while you sleep.
Plugin URL: https://wordpress.org/plugins/akismet/