Preview Frame adds the inline Preview window that was removed in WordPress 2.2
Buy Me a Beer – PayPal Donations Plugin allows your blog readers to donate money to you via PayPal.
wp-forecast shows the weather-data from accuweather.com (Page in German)
Spider Trap converts email address in your page header, title, content and comments into HTML conform ASCII values.
TinyMCE Advanced enables most of the advanced features of TinyMCE, the WordPress’ WYSIWYG editor and adds 12 plugins to TinyMCE.
FireFox Popup displays a link to IE users asking them to download Firefox. You can use also use you adsense referral buttons.
gWatchMyBack24h checks an incoming comment/trackback against the existing of a valid backlink (trackback) or against a very small list of keywords (Hooray-Jobs/BBCode). If it fails the comment/trackback will shown as spam to you in the admin management of your WordPress installation.
WenderHost Subpages Widget is a widget for displaying a list of subpage links. The list remains consistent regardless of where you are in the hierarchy.