Green tea. Green tea is one food-drink that can increase your metabolism and it has antioxidants. Other drinks that might increase your metabolism would be those that contain caffeine- cause caffeine would increase your metabolism. Please use moderation, as too much of a good thing can cause heart palpitations and irregular heart beats, as well as jitteriness.
No special foods. Humans are adaptable to all sorts of foods. There are no special foods that have a noticeable effect on one's metabolism rate. Usually, whatever snacks one enjoys should be fine. The best snacks are the healthiest ones, meaning ones containing protein, whole grains, "healthy" fats, and little sugar. Caffeine and other stimulants are not recommended, even though they may increase metabolism.