Boris Kuzmanov

This plugin lets you remove menu items with drag & drop. It basically simplifies the process of deleting the menus which can be really time consuming if you have a lot of menus. sTRASHo is located in your Appearance > Menus menu.
https://www.youtube.com/watch?v=swz5INhnDr4

sTRASHo

sTRASHo is a smart and easy way to delete your menu items.

Avendi Media

Menu Tamer adds collapse/expand links to nav menu items in the WordPress admin interface. If you have a large navigation menu, managing it can become a frustrating task due to the sheer size it takes up. Menu Tamer lets you collapse any branch of a nav menu to get it out of the way.
Menu Tamer has been tested in the latest versions of Chrome, Safari, and Firefox, as well as Internet Explorer 7, 8, and 9 (understandably, it is much slower in IE, but it works).

Menu Tamer

Adds collapse/expand links to menu items to de-clutter the nav menu interface

sTRASHo vs Menu Tamer