philipwalton

WARNING: This plugin is no longer being supported by its developer and may not work with future versions of WordPress. A replacement by the same developer is available called <a href="https://wordpress.org/extend/plugins/pw-archives/" rel="ugc">PW_Archives</a>. It’s faster, more efficient, and implements the latest WordPress security features.
This plugin makes the posts in your nav easily-groupable by month and year. It gives you 
quite a few easy-to-implement options that allow you to customize both which date groups are 
listed as well as how the markup is structured.
Perhaps the primary benefit of this particular plugin over other plugins that do similar 
things is its ability to enclose the post count within the anchor tag. This solves countless 
problems for anyone using the CSS style display: block on anchor tags, which produces the 
undesirable result of forcing the post count down to the next line.

Simple Nav Archives

Allows you to group your archives by month and years with several customization options.

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().

Simple Nav Archives vs Subtitle Filter