The list varies each time we upgrade cPanel. New scripts are added at regular intervals. Sometimes a particular script will be replaced altogther. At the time this article was written the list of scripts was as follows:

Blogs
     b2evolution 
     Nucleus 
     pMachine Free 
     WordPress  
      
Content Management
     Drupal 
     Geeklog 
     Joomla 
     Mambo Open Source 
     PHP-Nuke 
     phpWCMS 
     phpWebSite 
     Post-Nuke 
     Siteframe 
     TYPO3 
     Xoops 

Customer Relationship
     Crafty Syntax Live Help 
     Help Center Live 
     osTicket 
     PerlDesk 
     PHP Support Tickets 
     Support Logic Helpdesk 
     Support Services Manager  
      
Discussion Boards
     phpBB2 
     SMF  
      
E-Commerce
     CubeCart 
     OS Commerce 
     Zen Cart  
      
F.A.Q.
     FAQMasterFlex  
      
Guestbooks
     ViPER Guestbook  
      
Hosting Billing
     AccountLab Plus 
     phpCOIN  
      
Image Galleries
     4Images Gallery 
     Coppermine Photo Gallery 
     Gallery  
      
Mailing Lists
     PHPlist  
      
Polls and Surveys
     Advanced Poll 
     phpESP 
     PHPSurveyor  
      
Project Management
     dotProject 
     PHProjekt  
      
Site Builders
     Templates Express  
      
Wiki
     TikiWiki 
     PhpWiki  
      
Other Scripts
     Dew-NewPHPLinks 
     Moodle 
     Noahs Classifieds 
     Open-Realty 
     phpAdsNew 
     PHPauction 
     phpFormGenerator 
     WebCalendar