microkid

This generates meta descriptions for your posts automatically, using the format explained on the Official Google Webmaster Central blog in <a href="http://googlewebmastercentral.blogspot.com/2007/09/improve-snippets-with-meta-description.html" title="Improve Snippets With Meta Descriptions" rel="nofollow ugc">this article</a>. It uses author, post date, categories, number of comments and, when available, tags.
<h3>Compatibility</h3>
Although this plugin is still in BETA it should work with these other plugins:
<ul>
<li>Ultimate Tag Warrior – If you are using WP 2.3+ with native tag support my plugin will use those tags, if you have a lower version and UTW installed it will use those.</li>
<li>All in One SEO Pack – Make sure you switch of the “Autogenerate descriptions” option for this plugin or you will have two meta descriptions in your page, which can’t be good!</li>
<li>TDO Mini Forms – My plugin will grab the author of the article when it’s been submitted through this plugin.</li>
</ul>

Improved Meta Description Snippets

This generates meta descriptions as advised by the Official Google Webmaster Central blog.

Ajay

WebberZone

Do you want to customize your site with code but don’t want to edit your theme files or worry about losing your changes when you switch themes? Do you want to add analytics, site verification, custom CSS, or any other code to your site without using multiple plugins? Do you want complete control over where and when you display your code snippets on your site?
If you answered yes to any of the above questions, WebberZone Snippetz is the perfect plugin!
<a href="https://webberzone.com/plugins/add-to-all/" rel="nofollow ugc">WebberZone Snippetz</a> (formerly Add to All) is a simple yet powerful plugin that allows you to create and manage custom snippets of HTML, CSS, or JS code and add them to your header, footer, content, or feed. You can also choose where and when to display your snippets based on criteria such as post IDs, post types, categories, tags, and more.
WebberZone Snippetz comes with out-of-the-box support for Google Analytics and Statcounter. It lets you easily add meta tags to verify your site with Google, Bing, and Pinterest.
WebberZone Snippetz also enhances your site’s feed with a copyright notice and a link to the post. It also comes with many actions and filters to extend its functionality.
Here are some of the key features of WebberZone Snippetz:
<ul>
<li>Create custom snippets with HTML, CSS or JS code</li>
<li>Add snippets to your header, footer, content or feed</li>
<li>Choose where and when to display your snippets based on post IDs, post types, categories, tags, and more</li>
<li>Support for Google Analytics and Statcounter</li>
<li>Site verification for Google, Bing and Pinterest</li>
<li>No need to edit theme files or lose changes when switching themes</li>
</ul>
WebberZone Snippetz is the ultimate snippet manager for WordPress users who want to customize their site with code. Download it today and see the difference! 
WebberZone Snippetz is one of the many plugins developed by WebberZone. Check out our other plugins:
<ul>
<li><a href="https://wordpress.org/plugins/contextual-related-posts/" rel="ugc">Contextual Related Posts</a> – Display related posts on your WordPress blog and feed</li>
<li><a href="https://wordpress.org/plugins/top-10/" rel="ugc">Top 10</a> – Track daily and total visits on your blog posts and display the popular and trending posts</li>
<li><a href="https://wordpress.org/plugins/knowledgebase/" rel="ugc">Knowledge Base</a> – Create a knowledge base or FAQ section on your WordPress site</li>
<li><a href="https://wordpress.org/plugins/better-search/" rel="ugc">Better Search</a> – Enhance the default WordPress search with contextual results sorted by relevance</li>
<li><a href="https://wordpress.org/plugins/autoclose/" rel="ugc">Auto-Close</a> – Automatically close comments, pingbacks and trackbacks and manage revisions</li>
</ul>

WebberZone Snippetz – Header, Body and Footer manager

The ultimate snippet manager for WordPress. Create and manage custom HTML, CSS, or JS code snippets and control where and when they are displayed.

Improved Meta Description Snippets vs WebberZone Snippetz – Header, Body and Footer manager