I've got Robe of the Archmagi, once. It was annoying, because I got TWO great treasures on the turn I lost against AI as Mictlan, and the reason I lost because I couldn't summon an Arch Devil because I lacked a booster. I think that must be some kind of a hard-coded learning experience.
In my SP Bogarus game I got Baba Yaga on the 1st turn, and on the 2nd turn I got a Dwarven Hammer from and event, and another Dwarven Hammer from the indy province I conquered. I take luck 3 in most of my SP games, just because it's fun and the lost points serve to help the AI a little.