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().

hptheme

This plugin helps you to delete an menu item and its sub items very easily.
You don’t need to click on an item, then click “Remove” link. Just click “x” button (to delete an item) or click “xx” (to delete an item and all its sub items)

Quick remove menu item

Works great in WordPress 5.0.1 - thank you! Saved me a lot of time going through menu items one by one to remove them.

Works Well

No issues in 5.2.1. Thanks for the effort with this plugin.

Subtitle Filter vs Quick remove menu item