i'm pretty sure Corwin is thinking of one of the 2 gotha runes. i think Gorath is right about it being in the caverns that are to the right after you enter lower part of gotha. also i'm pretty sure it is not in the main center area but all the way back in one of caves 'limbs'. i believe it was lying among crates and or a tombstone.
Walk straight into Gotha, and turn right as the you reach a "T-crossing". There should be a cave with skeletons whose interior looks a bit like a store room. The rune can be found if you take stars down from that cave.
Right full list is posted in spoiler forums, also someone cleaned it up and posted in the wiki, was it hard to find Bodycount02, search not working or wili broken?
Usually locations of items are located in spoiler section, I hope they are still there.