Oh yes there is !!! but it is rare to find something good but still there are some people that has something very powerful or special. The ring of regeneration that you know now, And if you are skilled master, try to steal Kangax. You get his ring. The best pickpocket if from merchand when you see the items list he is selling. In the drow city, I stold the firetooth dagger and all the good stuff availlable. Spells are very cool to steal since there are very expensible. Drink 3-4 thief potion to have a better pickpocket score and take them all!!! I did not buy a single spell in the game.
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Maybe it's because I hate drows more than I hate Humans - Jarlaxle to Entreri