I'm interested as well into where everything is, so I took some time to look up some of the stuff
Mysterious Vial + Contaminated Ore.
If you talk to Berrun with: The scroll which gives Mulahey his orders, or Mulahey's holy symbol, and some contaminated ore, or the Mysterious Liquid, Berrun will give you some help to push you in the right direction. If you talk to Thalantyr wit the Liquid, he will take it, and point you in the direction of Taerom Fuirium. In MY game, it was difficult to get him to accept the iron ore, but to do it, I had to have a piece of ankheg first. That's all.
Quoningar
In the Three Kegs, Quoningar is up on the second floor. He wants a potion of mind focusing. If he really likes you (NPC Reaction 15+), he'll give you a hammer +1. If he doesn't really like you, you'll only(!) get 2 potions of Magic Blocking. Note that he doesn't have the 2 potions on him, but does have the hammer on him. You can charm him, then pickpocket the hammer if you really want it. The problem is actually finding a potion of mind focusing. With FotD installed, I have about a 1 in a billion .45% chance of getting one from the very few RNDTRE05 items in the game. Sorcerous Sundries surely sells some succulent spirits...
Shilo Chen
Shilo, in the Elfsong Tavern, wants you to kill 2 Ogre Mages in the Bandit Camp. Easy new pickpoceting gloves.
Corianna
In the Temple by Beregost, Corianna has been petrified. If you help her, and she likes you, she'll give you a potion of mirrored eyes. The exp ranges depending on what you say, and whether or not she likes you or doesn't like you.
Farmer
In the Bridge to BG, a farmer will approach you and ask you to help out with the dumping in the lakes around here and in the wood of sharp teeth. I don't know anything about this quest, and was hoping someone else could help.
Edie, the Merchant League applicant
In the Merchant League (note you have to help out Aldeth before chapter 5), Edie is on the second floor and wants some help on her exam. If you had a potion of genius, insight, or mind focusing, you'd take it right before a test, right? She'll give you 50 gp for any of them, though on mine, she should have drunken the potion before she payed you, because she tries to give you 500 gp. Of course, from what I can tell (I haven't quite done the quest yet), she won't actually give you ANYTHING because the trigger GivePartyGold only works on what gold you currently have, and she doesn't have any on her. I hope if I'm right that this bug is already reported.
I don't know of the others yet, but I'll keep looking.