From what I’ve seen:
In each vision there’s a note on the ground talking about the potions, and a corpse nearby with a potion in its hand. Just don’t drink the color it’s holding, the rest are safe (either giving mediocre buffs with drawbacks when they fade, or the one good one giving 100 sanity)
In org it’s in a hut on the left in the first area (between the bank and the forge), and in stormwind it’s just in the corner by the archer/mage pack straight ahead as you enter. The note should be outlined as something you can click on.