disinfor

A text widget based on the default WordPress text widget. Allows users to add custom classes to the widget container and the title tag.
It takes this: 
<h3 class=”widget-title”>
And allows you to do this: 
<h3 class=”widget-title custom-class custom-class-2 etc”>
It also allows users to add custom classes to the widget container.
NEW 
If the sidebar registration in your theme’s function file does not contain any HTML for before or after the title of the widget, this now will now fill that with an <code><h4></code> tag set.
<h3>General Information</h3>
This plugin is absolutely free to use. I made it for a specific personal purpose and decided to share with everyone else. I will try and update this for the future but can’t guarantee.

Text Widget with Class

A text widget based on the default Wordpress text widget. Allows users to add custom classes to the widget container and the title tag.

duzymaju

This simple plugin was written to add classes to first, last, parent, even and odd elements of wp_page_menu and wp_nav_menu to support recognizing it in older browsers without :first-child, :last-child and :nth-child supporting.
Plugin adds the following classes to menu <li> tags:
<ul>
<li>“first-menu-item” to every first child of <ul> or <menu> tag,</li>
<li>“last-menu-item” to every last child of <ul> or <menu> tag,</li>
<li>“parent-menu-item” to every child of <ul> or <menu> tag that has another <ul> or <menu> tag inside (a parent to another menu level),</li>
<li>“odd-menu-item” to every odd child of <ul> or <menu> tag, including first and/or last child,</li>
<li>
“even-menu-item” to every even child of <ul> or <menu> tag, including first and/or last child.
Above classes are added separately to each menu level. Plugin use SimpleXML extension and requires PHP 5 or higher. Menu should have valid XHTML code.
</li>
</ul>

MAJpage Menu Class Extender

Adds classes to first, last, parent, even and odd elements of wp_page_menu and wp_nav_menu.

Text Widget with Class vs MAJpage Menu Class Extender