I don't know about those two--will check them out (I'm not a big Bjork or Sigur Ros fan, though I appreciate their work). My favorite two are Olafur Arnalds (the ambient / pianist--there seem to be two musicians with that name) and the transplanted Low Roar. Here's the latter's greatest (in my estimation) video: https://youtu.be/iPGvMTqkUok