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a WordPress plugin to manage custom fields for posts and pages.
an event management plug-in for WordPress.
An eCommerce plugin. The "famous" WooCommerce plugin was born out of a fork of JigoShop.
a plugin that supports e-commerce.
a video player that is also available as a WP plugin.
Alternative PHP Cache - a free and open framework that caches the output of the PHP bytecode compiler in shared memory, thus reducing parsing and disk I/O overhead for later requests; and a shared mem…
a form plugin that is no longer maintained by its original author. It has been taken over by a new crew under the name Cforms 2.
a plugin that automatically adds a mobile theme for mobile visitors to a WordPress website
a theme by Automattic, the creator of Wordpress, but questions are still off topic if they are specific about how the theme works.