the Original or BDJ's Rev2 Mod? AFAIK, there is no limit in the original. Once, just for fun in the original version, I multilooted Morcarak on EI for 13 Artifacts/Relics and then Wromthrax for another 10 or so. I picked up 15 or 20 more in various places like Clanker's Lab, Colony Zod, the Dragon Caves, etc.In BDJ's Mod, however, there are quite a few artifacts/relics lying around after certain major battles and several on high level monsters. It seems to me though that there are fewer artifact/relics available in the mod than in the original game.
Could be my imagination though.