The list is quite long actually. GS, has model exporters for Battlezone II Combat Commander, Genesis3D, UDK, Torque, Blitz 3D, Half Life, UT2003, Serious Sam, Unreal/UT, Sims, Quake 2 and 3 and Game Studio A5/A6. Additionally it also supports several popular formats like X, 3DS, Macromedia W3D, and ASC. There are also several other TSX based export plugins originally written for Truespace 3D like UDK, ASE, UR, PSK, and PSA that will load and run under Gamespace.
Gamespace, was originally designed as a simple 3D modeling software that catered to the video game market. Like it's Truespace equivalent Gamespace is quite simple in design and very easy to learn by the average human being.
Alhough no longer available for purchase by Caligari Corporation a licenced copy can still be obtained from previous owners willing to part with their license to Gamespace. There is also a free demo version hosted on this forum for those interested in trying Gamespace.