WordPress currently supports more than 54,000 plugins. Of the 54K, some have seen more than 1.25 billion downloads. 19 of those have surpassed 1 million installations. (Source: dataport.net)
The most popular plugins are:
Hello Dolly, W3 Total Cache, Contact Form 7, Really Simple CAPTCHA, All in One SEO Pack, Google Analytics by Yoast, Google XML Sitemaps, WordPress Importer, Regenerate Thumbnails, WooCommerce, WP-PageNavi, WP Super Cache, Jetpack, TinyMCE Advanced, NextGEN Gallery, Wordfence Security, Yoast SEO, Advanced Custom Fields and Akismet. (list by dataport.net)
Still thinking twice about trying WordPress? 40% of the internet can’t all be wrong. Give it a try!