This document discusses various Symfony plugins that are available. It provides examples of some commonly used plugins such as sfCSRFProtection, sfDoctrine, sfFeed2, sfFlickrGallery, sfGravatarHelper, sfJpGraph, sfOpenID, sfOpenOffice, sfPokaYoke, sfShoppingCart, sfSugarCRM, and sfSimple plugins. The document encourages developers to write their own plugins and lists resources for finding more plugins.