Depends what for, you could either rip off a real team name (my HS team is called the thunder), or make a new team name. Some examples of this could be the Lightning, Soldiers, the Flames, the Steam, the tornadoes, the eagles, the hawks, the tigers, the Pride (as in Pride itself or like a pride of lions), The vultures etc. Basically think of an animal or a natural phenomenon that is menacing or intimidating in some way.