Floating Tweets adds a floating, slide out tab containing the latest tweets from any twitter account.
Random Redirect 2 makes it easier for the average user to create a stumbleupon-like experience on any website and restrict the randomness to certain tags and keywords.
Social Metrics is a social media analytics tool you can use to track your WordPress blog performance on popular social networking websites and services.
Amazon Tools allows you to retrieve and display Amazon product information in your blog.
Simple Twitter Connect is a series of plugins that let you add any sort of Twitter functionality you like to a WordPress blog.
Slick Contact Forms creates a widget, which adds a contact form using either a floating, drop down button or a sticky, sliding tab.
Ultimate Post Type Manager allows you to easily customize post types.
WordPress MU Sitewide Tags Pages provides a central area where all the posts on a WordPress MU or WordPress MS site can be collected.