| off the top of my head, there are one of each of those barrels in the main halls, I either constitution has two on that floor
there are wells that once the quest linked to them is finished will give you a boost to your constitution, charisma, and wisdom
there is another well that will boost constitution by several points, but drains charisma and dexterity a bit
and much later in the game, in the drow catacombs, there is a barrel for each stat that give you a boost of two points, unless your stat is 18+, then you only get a one point boost |