Kumbh Design Inc.

You can set meta tags like keyword, description. You can customize on each individual page/post as well.
<h3>Features</h3>
<ul>
<li>FREE Plugin.</li>
<li>One click to Install.</li>
<li>Simple and Easy to Use</li>
<li>Do not need to edit your theme’s core files.</li>
<li>Quick and supportive.</li>
</ul>

WP Simple Meta Tags

Allows you to set meta tags like keyword, description and you can customize on each individual page/post.

Purab

Boost your wordpress SEO: Full SEO features Meta Tags, webmaster tools settings, Social AuthorShip for Facebook, Twitter and Google Plus and XML sitemap
You can enter your meta keywords and description for your homepage.
This plugin will add different Meta description for each individual post as your excerpt of your post.
This will help your blog to rank better in google. You can easily increase your blog traffic using this plugin.
New Premium Features Added
WebMaster tool and meta tag added
Social AuthorShip meta Tags added for Facebook, Twitter and Google Plus
XML sitmap added
Following Sites are using SEO meta tags: 
Demo URL: 
http://wpapi.com
<a href="http://wpapi.com/how-to-use-seo-meta-tags-wordpress-plugin/" rel="nofollow ugc">Step by step installation instructions >></a>
Tested upto 4.0
<a href="http://wpapi.com/contact/" rel="nofollow ugc">Click here for customer support >></a>
<h4>Functionality</h4>
This plugin will add different Meta description for each individual post as your excerpt of your post.
<h3>Help</h3>
For help and support please contact us at contact [at] digcms.com 
<a href="http://wpapi.com/contact/" rel="nofollow ugc">Click here for customer support >></a>

Seo Meta Tags

Boost your wordpress SEO: Full SEO features Meta Tags, webmaster tools settings, Social AuthorShip for Facebook, Twitter and Google Plus and XML sitem …

WP Simple Meta Tags vs Seo Meta Tags