In the grove, there are at least 2 potential traders, and I think it can have 3. The goblin outpost has 1, but that is a refundable one after going ham out there. There is a trader behind the burning mansion if you do that quest, and they would have a high chance of having one on them. Of course, underdark has a couple in the Myconid camp as well, and I think they have one for sure.