alpipego

This plugin makes long and complex navigation menus better manageable by creating groups that can be expanded and collapsed.
By default, all navigation menus in wp-admin will be collapsed. When holding the Option/Alt-key while clicking, all sublevels will be expanded with one click.
For general support, please use the support forums on <a href="https://wordpress.org/support/plugin/wield-menu" rel="ugc">wordpress.org</a> 
For developers: Head over to the <a href="https://github.com/alpipego/wield-menu/" rel="nofollow ugc">Github repository</a> 
For everything else, find me on <a href="https://twitter.com/alpipego" rel="nofollow ugc">twitter</a> or slack

Wield Menu

I had this problem when working on themes demo as they have all possible page in the menu.

Thanks!

Very handy

Make long and complex Navigation Menus wieldable

Rupok

Codetic

Search box on Navigation Menu allows you to add search form in your site navigation bar that makes users to search your site easily.
The plugin provides you various settings in the admin area which you can use to customize the search form.
<h3>Credits</h3>
Some functions adapted from the plugin <a href="https://wordpress.org/plugins/add-search-to-menu/" rel="ugc">Add Search To Menu</a> by Vinod Dalvi.

Search box on Navigation Menu

The plugin displays search form in the navigation bar which can be configured from the admin area.

Wield Menu vs Search box on Navigation Menu