Marcus Downing

When writing or modifying a theme, the function wp_nav_menu() displays the contents of menus configured in your settings. If you have a lot of little menus the list can get hard to manage, so this plugin lets you group several menus under a single menu.
To use it, simply add a <code>submenu</code> parameter to the arguments of wp_nav_menu, like so:
<pre><code>wp_nav_menu(array(
 'menu' => 'header',
 'submenu' => 'About Us'
));
</code></pre>

Subtitle Filter

Adds tha ability to show only a submenu with wp_nav_menu().

Robert Noakes

Simple plugin that allows for nav menu items to be copied with a single click. Copied nav menu items are added directly after the clicked nav menu item at the same depth. All field values, including custom fields, are duplicated as well.
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Copy Nav Menu Items

Simple plugin that allows for nav menu items to be copied with a single click.

Subtitle Filter vs Copy Nav Menu Items