Utkarsh Kukreti

This plugin allows you to list the terms of any taxonomy in the form of a widget. 
Supports several options to select, order, and display the terms.

Taxonomy Terms Widget

This plugin allows you to list the terms of any taxonomy in the form of a widget. Supports several options to select, order, and display the terms.

danielauener

A widget that simply gives you related posts by taxonomy. It provides four 
settings to customize every widget and there are no global settings to worry 
about.
Widget settings
<ol>
<li>The title of the widget (default: Related Posts)</li>
<li>The taxonomy by which terms the posts are related (default: Tags)</li>
<li>How many related posts to show (default 5)</li>
<li>excludet terms</li>
</ol>
The widget is visible only when <code>is_single()</code> is true, it doesn’t shows up on 
archives, search templates etc.
Translation credits
Thanks to Borisa Djuraskovic from <a href="http://www.webhostinghub.com" rel="nofollow ugc">http://www.webhostinghub.com</a> for the Serbian translation!

Simply Related Posts

A widget that simply gives you related posts by taxonomy. Four settings to customize the widget: title, taxonomy, related posts count, excludet terms

Taxonomy Terms Widget vs Simply Related Posts