(I'm taking this as a challenge)
Edge of Sanity
Nightingale
Unicorn
Dan Swano (Moontower)
Pan-Thy-Monium
Bloodbath
Odyssey
Wounded Knee
Karaboudjan
Route Nine
Infestdead
Godsend
Steel
Subway Mirror
he did some vocals for Therion on the "Theli" and "A'arab Zaraq Lucid Dreaming" records, drumming for Katatonia, as mentioned, I think he did the drums for Sorskogen, he's done some stuff for Diabolical Masquerade, and he's done stuff on his brother (Dag Swano AKA Tom Nouga)'s records.
... I think that's about it...
I've never heard Wounded Knee, Route Nine, Infestdead, Godsend, or Subway Mirror. I heard of sample of Karaboudjan and it was... unique, kinda akin to Pan-Thy-Monium. I think I'm going to send Dan an email and just order the R9 and Subway Mirror records... why the hell not?