chaimchaikin

Admin Menu Groups allows you to create nested menus in the WordPress admin sidebar navigation and organize all menu 
items in groups as needed.
A few notes about the sections above:
<ul>
<li>Create groups to organize the admin menu</li>
<li>Put less frequently used or advanced options in their own group</li>
<li>Hide unused items in the admin menu</li>
<li>Group related menu items</li>
</ul>

Admin Menu Groups

This is an underrated plugin. It is exactly what I expected: Keep my admin menu tidy since I see it almost everyday.

Especially impressive drag and drop tool. So I can make it works without finding any documentation like common plugins.

Thank you!

Underrated plugin

Admin Menu Groups allows you to create nested menus in the WordPress admin sidebar navigation and organize all menu items in groups as needed.

borantula

Most of the plugins and even standart WordPress tabs in the admin menu are not used very often. 
With this plugin you can make rarely used items in the admin menu invisible until you need them. 
You can just toggle them whenever you need them with Toggle Extra button in the left menu.

Clean WP Admin Menu

Still works!

You can make rarely used items in the admin menu hidden.

Admin Menu Groups vs Clean WP Admin Menu