With this plugin, you can add an automatically generated submenu for each menu item.
Automatically append children posts and pages as submenu items in the frontend
Hide the menus on the dashboard
Displays subpages for the current page. Set the depth and starting level (in hierarchy) and you are good to go.
Customize your header using WordPress Customizer API! Now you can live preview your changes while editing header options.
Gives you the ability to add custom links to the admin toolbar in addition to your frequently used admin and plugin links.
WordPress - Sidebar Accordion Menu Widget
Allows you to display a sub-menu, it's depth from there on and gives you control over the menu-item classes.
Embed WordPress Menus inside of other WordPress Menus!
Menu Obfuscator is a simple plugin that provides a intuitive interface to hide specific areas or menus on your Wordpress admin, for each user individually.
WordPress can only automatically add new top-level pages to menus. With Auto Submenu, new child pages will also be automatically added to menus.