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.

eroux

Display “Badges” in the side-panel which points to a web-site and an image which is then used to build the “badge”.
To access the configuration you have to go to Appearance > Widgets and edit the settings in the Panel.
Using the Widget you can choose whether to:
<ol>
<li>(Optionally) display a Title</li>
<li>Link to a site</li>
<li>Required link to an image to mark that site (any size will work, but the “standard” seems to be 88 pixels wide by 31 pixels high)</li>
<li>Pad the Badge (including centring the text); some people may prefer using their own CSS, so this is an optional configuration.</li>
<li>Enable “Display Badge in a Box” (enabled by default)</li>
<li>Enable the Displaying of a Drop-Shadow</li>
</ol>
If more control is needed, or more badges need to be displayed, the <a href="https://wordpress.org/extend/plugins/badges/" title="Wordpress Plugin" rel="ugc">badges plugin</a> on the WordPress site might be a better fit.

Badge

Display a badge (based the "badges") without requiring file-system access or knowledge of HTML.

Improved Meta Description Snippets vs Badge