turtlepod

<a href="http://genbu.me/plugins/fx-categories-widget/" rel="nofollow ugc">f(x) Categories Widget</a> will register a custom widget “Categories +” it’s just like WordPress default Categories Widget, but with taxonomy option just like in Tag Cloud widget.
Features:
<ol>
<li>Simple and easy to use.</li>
<li>Works flawlessly for multiple widget instances.</li>
<li>Select all build in taxonomy (such as category and tag) and all custom taxonomy.</li>
<li>Now you can display your Post Tags as list or drop down (not only as tag cloud).</li>
<li>The GPL v2.0 or later license. 🙂 Use it to make something cool.</li>
<li>Support available at <a href="https://genbu.me/contact-us/" rel="nofollow ugc">Genbu Media</a>. 
Notes for developer: </li>
</ol>
<h4>Github</h4>
Development of this plugin is hosted at <a href="https://github.com/turtlepod/fx-categories-widget" rel="nofollow ugc">GitHub</a>. Pull request and bug reports are welcome.

f(x) Categories Widget

Birchdunford

Tags, tagging, and post tags made easy. Stop thinking about what tags you should add, forgetting to add certain tags, and typing in tags by hand. Let Tagbag do the work for you. Just look at the list of suggestions, click the ones you want, and move on. More on Tagbag: 
<a href="http://www.explodybits.com/2012/04/tagbag-wordpress-plugin/" title="explodybits (xb)" rel="nofollow ugc">explodybits (xb)</a>

Tagbag

Tagbag, takes the thought out of selecting tags for your post

f(x) Categories Widget vs Tagbag