Pillars of Eternity

Go to the crafting tab by pressing LT in the inventory screen. Select 'Potions Level #" below Food. See what ingredients you need for three different potions and collect/buy them. If you do this later in the game there's a good chance you already have enough ingredients for three different potions. Just check to see which you can craft.

I'd advise to craft all three potions in one go because achievements in this game seem to be buggy.