Pickpocket usually yields some coin (copper at lower levels, silver later on), some potions (getting super healing potions frequently on my 68 Rogue), some gems (started with malachite and other types, now on to flame spessarite and other outlands gems), locked boxes (containing some coin, some vendor trash, some poison ingredients/powders, rarely a potion/gem/scroll/recipe)
At level 68, pickpocket has given me :
- All the Super healing potions I will ever need
- More Blinding and Flash powder than I can use (unless I sell on the AH)
- A maxed out lockpicking skill every level (I save 5 orange difficulty chests in bank/on alts for that next level up, opening the others, if they're yellow I keep 10 instead)
- A nice bonus cash prize
- Some mats for jewelcrafting
- Lots of vendor trash (Gnome Effigy, Shiny Bauble, Shark Bait, etc)
- Enough poison mats that keeping myself stocked with stacks of poisons costs me at most 2g per level (for vials/some mats I am not lucky enough to get)
In other words, picking pockets rocks (and only doable on Humanoid/Demonic mobs that have pockets and Slimes)