This plugin allows you to display your site's tags using a Flash movie that rotates them in 3D. By default it supports Latin and Cyrillic tags, for those who wants to display Chinese, Japanese, Korean, Arabic and Hebrew tags download a new swf file from here and replace the original one.
The Akismet plugin for b2evolution checks feedback through a central service ( http://akismet.com ) against spaminess.
This plugin is no longer necessary for most users because similar functionality has been integrated into b2evolution's core. To add a list of comments to your sidebar, go to Blog Settings > Widgets > Add Widget and click on Comment List.
This plugin adds a widget that displays a list of recent comments in your sidebar.
The YouTube Plugin allows you to search YouTube, select a video from the results and add it to your post. You don't need to have a YouTube account. You don't need to edit the b2evolution HTML Validator. You don't even need to go to YouTube.com. It's all done from inside your b2evolution backoffice.