A feature list from

's home page:
Over 10 new user-created missions
Single Player Templar Campaign
Single Player Gauntlet Missions
New multiplayer missions originally released on the web
Missions originally from the FreeSpace 2 demo
At least a partial list of missions included with the SOTY version:
John Crowdis - Rites of Passage
Paul Desjardins - To Destroy or Not to Destory
Michael Diedrich - The Queen, Shivan Incursion
Peter Drake - Boomerang
Kurt Heiner - The Cold Sword
Steven Holgate - Third Coming
Nathan Hoying - Third Watch
Alex Kirkwood - One Step Too Far
Simon London - The Trap
Curtis Luk - Sirius X
Michael Pureka - Excellence Under Fire
Solrazor - Nekhbet
Some missions may have been integrated into campaigns and/or have sequels available by now. (There appears to be some link between Rites of Passage, Derelict, and "Welcome to the Boonies" but I don't know the full details.)
Search is A1-Supar.

6th link I found with Altavista was the

Freespace page (
www.volition-inc.com/fs) which is where I got some of the above info from. And at least some of those missions are available in the VW Archives site. (Couldn't find the Templer and didn't see the Gauntlet ones though.)