There are two traders in the Druid grove.
There is a trader in the Zent hideout.
There is a goblin trader outside at the goblin encampment.
There is a halfling trader inside the goblin base.
There is a hobgoblin trader in the mycanoid camp in the Underdark.
There's also a dwarf trader in the Mycanoid Camp
Also "technically" a 3rd trader in that same camp (spoiler)
If you get the hobgoblin to call over his Mind Flayer friend, and then get the potion ingredients for him, he becomes a shop as well. Though his only good item is the mind shield ring.
