Usefull Yii Extension

Datafilter
This extension can be used to add search and filtration capabilities to data grids.
http://www.yiiframework.com/extension/datafilter/

grbac
This module is for User-Management
http://www.yiiframework.com/extension/grbac/

extendedclientscript
With this extension you can transparently reduce page load times by combining and compressing the used Javascript and CSS files.
http://www.yiiframework.com/extension/extendedclientscript/

euploadify
This extension adds a flash based file-upload with progress-bar and multi-file upload capability.
http://www.yiiframework.com/extension/euploadify/

cfile
This extension offers commonly used functions for filesystem objects (files and directories) manipulation.
http://www.yiiframework.com/extension/cfile/

esanitizer
This extension sanitizes all user input ($_POST, $_GET, $_COOKIE,$_FILES) with html purifier to protect against XSS
http://www.yiiframework.com/extension/esanitizer/

cvsout
http://www.yiiframework.com/extension/csvout/reviews/

printout
http://www.yiiframework.com/extension/printout/