Chef magic, you have to eat or drink or use magically prepared items to get any effect.
I am making an effort to make it borderline useless here... if you want it more magical I guess you could imbue the things you eat with their foremost property (like eating something small makes you small), but that might be too useful?
Elemental
Eat a chili to spew a flame a few decimeters forward or something crappy like that.
Eat something foul smelling and people around you will get posionedpoisoned or nauseous from your bad breath.
Healing
Put a herbal cream on your wound and it will heal.
Eat a magic mushroom soup, this makes you more susceptible to psychosis but your ability to make up new magical recipes increases.
Transformation
Grease up some skin and wear it on you, and you will look like whatever wore the skin latest (or maybe originally?).
It is of course harder to wear skins that are smaller than you, so to do that you could collect a lot of them (for example skin from a school of fish) and put it on you (now you look like a school of fish!)
Maybe you could get inspiration from old snake oil adverts. Kindof as if the snake oil actually worked...