Every planet has to be filed in a class. This page disscuses those classes.
A dead world, Earths moon. They may possess a good metal supply.
Various types of gas giant.
A hot desert world. Taxxar.
A frozen artic world, Nahara.
Volcanic planet, Gormon
Rocky, cliff filled world with sparse vegatation that supports a moderate amount of life forms.
Like M, but possesses a differant atmosphereic composition, instead of Nitrogen/Oxygen, it could be something like Methain/Amonia. They usually support a wide variety of life.