There are no less than three types of rotations that teams use. They are the 4-2, the 5-1, and the 6-2. The first number denotes the number of hitters on the court and the second number the number of setters. In a 5-1, for example, there are 5 available hitters and 1 setter.
The 4-2 is common on lower-level teams where players are still trying to learn the basics of the game. The 5-1 and 6-2 are more common on higher-level teams with more experienced players.