Justin Tadlock

Ever had a widget get stuck in a particular sidebar or widget area? Are your widgets missing when you switch themes?
This plugin will remove all widgets, setting everything back to the factory settings.

Widgets Reset

Allows you to reset all of your widgets, wiping the slate completely clean.

Daniel Ostman

Separator Widget inserts a horizontal rule ( <code><hr></code> ) or a custom div ( <code><div class="my-separator"></div></code> ) in your widget area. Each widget can be set to one of those options.
No extra styling is added so you are free to style them however you want it. 
Add your custom <code>hr</code> styling to your CSS or use <code>.my-separator</code> if you prefer that option.
Free and easy to use!
<a href="http://www.danielostman.se/" title="Visit WordPress developer web site" rel="nofollow ugc">More info about the WordPress plugin developer</a>

Separator Widget

A widget that inserts a horizontal rule or a custom div.

Widgets Reset vs Separator Widget