In the game 2 kind of potions can be found on defeated enemies, in chests and other places or bought from merchants.
Restores life to maximum
Restores power to maximum
Apart from these you can get special potions as a reward for completing certain quests, which increase permanently the character's attributes with only 1 though.
this is made be Klissiere in the Refugee Camp, if you collect 5 Giant water spider eggs for him. The potion gives you +1 health.
this is brewed by Garilda in Cloudworks. For this she needs 5 pieces of mushrooms called Red octopus, which could be collected in the Sewers (they're at one place). You get +1 strength.
this potion is also a "patent" of Klissiere, and for this he needs 10 root lion claws. These are dropped by the Lionroots roaming around in Gaian. This potion gives you +1 agility.
this is distilled by Sormyr in Gaian, if you bring him 5 Beastmen's Runes. These Runes are not ingredients of the potion, but you can have it only if you take the Runes to Sormyr. It gives you +1 intelligence.
In the game two potions are made besides the above mentioned ones, but they have no direct effect on you - except for that you get xp for bringing the ingredients for them.
|Dragon bark potion:|
Lissae is the elf who makes this potion for the injured people in the Refugee camp. For the medicine she asks three dragon barks from you, which you can get by killing a Tree dragon. Your reward for the ingredients is some life and power potions, if you agreed in this before.
this is used for the people who got sick because of the water poisoned by the Zombies in Silverfall. Lissae makes this as well and for that she needs 1 vanom gland of an Urguln, which heals almost all poisoning. Urgulns can be found in Gaian. Your reward is some general potions, if you take the task with this condition.