It can be really hard to keep track of whats out there, due to the size of many of the game developers in Norway.
My impression is that there are very few studios that have been operational for more than a couple of years and have more than 5+ employees.
Funcom is the only major international developer with a long history and with a large group of people employeed both in Norway and Canada as well as Beijing.
Artplant ( http://www.artplant.no
) is another studio worth mentioning. Its a much smaller studio than funcom but it has been around for some time now. Check out their webpage to see what they do.
The only other companys that I know of are the two you mention, Ravn Studios & Terravision as well as the newly started Frost Software ( http://www.frostsoftware.com/
). Except for that there are a number of other smaller studios such as Inludo, Brilliantley Blonde, Plutonium Software and so on, but it is very hard to find information about smaller companys so I dont know which companys are operational anymore.
I often check this site to see whats out there, but often it is not updated but generally it gives a good imperssion of the major studios out there in Norway but also internationally.
http://www.gamedevmap.com/index.php?too ... query=Oslo