There are 4 main basic boxing punches that each have several variations. The 4 punches consists of the jab, right hand, hook, and the uppercut, which covers basically all angles of punching with its variations. When you bring in martial arts, there are even more variations of strikes using the arm.
For the uppercut, it can be one of the more dangerous punches despite not generating as much force as the hooks or right hands (left if southpaw). This is because an uppercut targets the chin and it can scrape the nose upwards. In addition, if you are bending over, then it makes you a prime target for an uppercut.