Zen Grid Framework v5 (zgf5) themes come with a simple Joomla plugin to replicate some key Mega Menu functionality in your Joomla site. The Zen Menu plugin can be downloaded here - please note that the plugin will only work with the html overrides found in zgf5 based themes.
Subtitles and Font Awesome icons
The Zen Menu plugin gives you the ability add icons and subtitles to any menu on your site using the core Joomla menu module.
Add a module positions to your menu
The plugin also make it possible to load a module position in any menu item.
Add multiple columns and group items
It is also possible to create multi-column and grouped menu items.