Yuki Sugitani

This plugin allows you to organize the contents of the head tag that WordPress automatically outputs. 
You can use the checkboxes to choose which tags to remove.

Tidy Head Tag

This plugin allows you to organize the contents of the head tag that WordPress automatically outputs.

satourne

Head Meta Date (formerly “Head Metadate”) improves the definition and semantic quality of your web pages by adding a set of date <code><meta></code> tags to the <code><head></code> section of your web pages.
Example
<pre><code><head>
 ...

 <meta http-equiv="Date" content="Wed, 16 Feb 2011 22:34:13 GMT">
 <meta http-equiv="Last-Modified" content="Wed, 17 Feb 2011 12:34:13 GMT">
 <meta name="CreateDate" content="Wed, 16 Feb 2011 22:34:13 GMT">
 <meta name="Last-Update" content="Wed, 17 Feb 2011 12:34:13 GMT">
 ...
</head>
</code></pre>
Features
<ul>
<li>Plug-n-play functionality</li>
<li>Easy to configure from the WP Admin</li>
<li>Adds set of meta tags to <code><head></code> section of posts and pages</li>
<li>Customize each <code><meta></code> tag with your selected date info</li>
<li>Leaving any field blank generate a now date</li>
<li>Auto-generates known information from your site</li>
<li>Choose HTML or XHTML format for meta tags</li>
<li>Enable/disable plugin output from the settings page</li>
<li>Includes live preview of your meta tags and custom content</li>
<li>Option to reset default settings</li>
</ul>
This plugin is designed to complete a site’s head construct by including some of meta tags. 
Note: the metadata output via this plugin applies to the entire site.
<h3>Donations</h3>
I created this plugin for my usage and decied to share with the WP community. I completely use the Head Meta Data WordPress plugin. 
Send some stars to Jeff Starr.
Links, tweets and likes as you want …

Head Meta Date

Head Meta Date adds a set of date <meta> tags to the <head> section of all posts & pages. This is a fork from http://wordpress.

Tidy Head Tag vs Head Meta Date