Badi Jones

Duplicate Content Cure is an extremely simple plugin that makes WordPress more Search Engine 
friendly (And therefore improving SEO). It does this by preventing search engine spiders/bots 
from accessing pages like Archives, Tags, and Categories, which tend to contain duplicated content 
from elsewhere on your site. This is achieved by adding nofollow, noindex to 
these problem pages.
Duplicate Content Cure doesn’t have a lot of features that other SEO plugins have, but 
it also is lightning fast by comparison.

Duplicate Content Cure

Duplicate content cure is a simple plugin that improves SEO by preventing search engines from indexing pages that contain duplicate content.

DesignSmoke

<h3>Advanced Spintax Post Generator – Spintax Plugin for WordPress</h3>
Advanced Spintax Post Generator allows you to quickly create posts using your spintax templates.
Create multiple locations, events, posts and pages without duplicate content penalties using this free WordPress spintax plugin. For example, if you have multiple stores that all offer the same products, you can quickly create unique pages for each one.
This is a completely free (GPLv2) plugin created by <a href="https://www.designsmoke.com/" rel="nofollow ugc">DesignSmoke – Portland Web Development</a>
Features
<ul>
<li>Avoid Duplicate Content Penalties</li>
<li>Spin titles, descriptions, slugs, tags and categories</li>
<li>Supports all custom post types</li>
<li>
Create as many posts as you want
</li>
<li>
(Future release) Create templates for easy re-use
</li>
<li>(Future release) Featured images</li>
<li>(Future release) Create posts for each keyword in a list (EG: Store San Diego, Store Dallas, Store New York City)</li>
</ul>
FAQ
<ul>
<li>Can I modify this plugin?</li>
<li>Yes! The plugin is <a href="http://www.gnu.org/licenses/gpl-2.0.html" rel="nofollow ugc">licensed under the GPLv2 License</a>.</li>
</ul>

Advanced Spintax Post Generator

Advanced Spintax Post Generator - Spintax Plugin for WordPress

Duplicate Content Cure vs Advanced Spintax Post Generator