Add to All is a powerful plugin that will allow you to add custom code or CSS to your header, footer, content or feed.
Add to Feed is a feed enhancement plugin that allow you to add a copyright message to your feed as well as custom text/HTML before and/or after your post content.
This plugin will let you easily display your Alexa traffic button or graph.
Close comments, pingbacks and trackbacks on your post automatically at intervals set by you
Display a list of contextually related posts for the current post. You can select the number of posts to display and if you want to automatically display the related posts in your content / feed.
GreyBox is a script can be used to display websites, images and other content in a beautiful way. GreyBox Integrator provides a one-click installation of GreyBox on your WordPress blog.
This plugin will notify the author of the post in addition to the admin. This will allow the author to moderate the comments too.
Add a reddit button to your blog post
Count page views on posts and display a list of top posts by page views.
Keeps your email safe from spammers when you want to use mailto: links.
Integrate TwitterCounter.com badges on your blog to display the number of followers you have on Twitter
This plugin will show “Readers who viewed this page, also viewed” links on your page. This is similar to Amazon’s product pages which state “Readers who have bought this, also bought”.
WP-Niceforms provides a one-click installation of Niceforms on your WordPress blog.