To date I have written and released a total of 5 add-ins for the Windows Home Server Console, all of which are freely available:
DHCP4WHS - A fully functional, written from scratch DHCP Server written entirely in managed code
Web Folders 4 WHS - Brings secure & remote drag-and-drop file access to Windows Home Server
Tab Reorderer - Allows a user to easily change the order of the tabs in the Home Server Console
Tab Scroller - Brings mouse scrolling to the tabs in the Home Server Console
Tab Manager - Allows user specified Home Server Console add-in tabs to be loaded within a separate, stand alone list for better organization