I found some artifacts in the plane of fire which I visited first, but none in the other 3 planes. Is there an artifact limit I remember reading somewhere about? Also, correct me if I'm wrong, but selling artifacts I already own, won't help me, right (there is the explosive bow I'd be willing to sell if it means I can get a better artifact later...)?

Thanks! So it seems it's different than 6 and 7.

I'm not really interested in getting all the artifacts, so I don't mind if I missed any.