ChartBoot allows to create, edit, and embed Google Charts in WordPress Posts or Pages.
Fast Flickr Widget lets you add a widget to show your Flickr photos.
Widget CSS Classes adds custom widget classes and IDs plus first, last, even, odd, and numbered classes to your widgets.
Genki Youtube Comments allows you to grab YouTube video comments and insert them into your own blog.
Jetpack supercharges your self-hosted WordPress site with the awesome cloud power of WordPress.com.
Simple:Press Forum is a feature-rich forum plugin.