Visual Composer offers a powerful API which allows 3rd party developers to implement their own add-ons, and sell them on CodeCanyon as stand alone plugins. VC offers the most comprehensive list of add-ons available of all plugins sold on CodeCanyon, highlighting the power behind this awesome Drag & Drop Page Builder Plugin.
Lifetime Updates free of charge. Front-end AND Back-end Page Editors. There are now 20+ add-ons available for Visual Composer, making it one of the most powerful and most customisable WordPress plugins available.