The latest and last for today:
--
Invictus: In the Shadow of Olympus - selected tracks on the composer's (Richard Band)
site. Look under INTERACTIVE GAMES AND VIDEOS.
Sadly nth for Conquest of the New World or Stonekeep.
--
Iron Storm - I'm starting to think that there's no proper soundtrack for this one, its Mobygames page only lists a Sound Studio (TALK OVER Inc.) with no info/ entry for music/ composer(s); maybe owners of the game on GOG can shed more light.
--
Legacy of Kain: Defiance - you probably noticed it yourself, but I followed a link to the Nosgothic Realm site from the Legacy of Kain The Lost Worlds page you added for the other Legacy of Kain games. A soundtrack can be found
here. The mentioned Read Me file is quite detailed, but it is a complete rip of the in-game music, plus recordings of the Prologue, Epilogue and End Credits.
Also, check your PMs about a couple of other games.