Unless stated otherwise, magical potions grant the drinker a given magical ability for 1d6+6 turns. And get rid of those generic potion bottles by using the Random Potion Container tables.
Mage Blood, Lesser
This potion is made from the blood of a magic user of level 4 or lower. It is not consumed, but is smashed on the floor while casting a spell. The target of the spell makes any saves against the effects of the spell with a -1 penalty.
Mage Blood, Greater
This version of the Mage Blood potion (above) is much rarer, requiring the blood of a magic user of at least fifth level. It is treated as its lesser cousin, but produces a -2 penalty.
The user gains the benefits of the water breathing spell. This wine is usually found in a larger bottle than most potions, containing 6 ‘doses’ of the potion.
Saddle Born’s Draught
The user gains the benefits of the Horseman’s Potion (+1 on all attack rolls and saving throws while mounted, and his mount gains these same bonuses), and also gains the ability to speak with horses, hippogriffs, griffons and pegasi.
This potion eliminates the need for food or drink for 1d6 days. The user feels neither hunger nor thirst but can still eat or drink if he pleases. At the end of the duration, there are no ill effects from having not eaten or drunk for the duration.
After imbibing this potion, the user casts no shadow. Instead a shadow replaces his natural shadow and follows his orders, even to the death. It can travel up to 240 feet away from the user in pursuit of its orders.