Tiger Barbs and Serpae Tetras are known to be aggressive and will play roughly among their shoal. You could get a big group in that tank, and they would be very active!
Betta are known for their high activity level and agressive feeding as well. Some people have even trained theirs to jump a short height out of the water to snatch food from the tip of their fingers!
Dwarf puffers are agressive and just the right size for a ten gallon tank. They take a bit of specialized care, so you should do some research
Another specialized hunting fish is the African Butterfly Fish. They are even more finicky than the puffers though, and need research as well.