Contact Form plugin from 123ContactForm.com. It requires a free account on 123ContactForm.
Integrates the BTBuckets service into your WordPress blog, giving your blog the ability to dynamically morph depending on who your visitors are. Now you can target your visitors based on their visiting behavior
The plugin is ideal for blogs with multiple authors and acts as an incentive for making quality posts. When the add-on is enabled, users will have full control over the advertisements displayed on their own posts. Using a space pre-allocated by the blog administrator, authors will be able to display various forms of advertisements in addition to accepting Paypal donations
GetSocial adds a lightweight and intelligent floating social media sharing box on your blog posts.
WordTour offers you a no-fuss time-saving solution to events management and a whole lot more
This contact form is floating, hidden in the left side of your page, if its button clicked, the plugin will slideout
This plugin sets a “version” cookie of your site’s content, which can be used for time-based cache invalidation, as the cookie is checked and updated (if necessary) on each page request through a single AJAX request.
Easily add actionable social sharing buttons to your posts on a page to page basis or across your entire site with ease.
This plugin allows users of a WordPress MU site or WordPress 3.0 network to map their blog/site to another domain.
This plugin provides a button to be installed into the Google Picasa Desktop to directly upload files from Picasa as WordPress media.
An all-in-one SEO solution: title tags, meta, noindex/nofollow, canonical, 404s, slugs, autolinks, hReview rich snippets, and more
This plugin has option to add Google, Bing, Alexa, Blog Catalog, Yahoo’s Webmaster and Analytics code (meat tags).