Human: A Human is one of the weaker races in DB/DBZ/DBGT. They don't have any special attacks, but can still fight with there hands and feet.
Saiyans: The saiyans are the best race in Dragonball Z. They were all born on planet Vegeta and then are taken to planets to destroy there life forms. The Saiyans are a group who like to kill. Goku wasn't this way because he hit his head when he was young.
Tsfurujin: The Tsfurujins were a group just like humans who had tecnlogy like scouters and space pods. They lived on Planet Plant which was changed into Planet Vegeta. Most of the Tsfurujins were killed except for Baby who was eventually killed by SS4 Goku.
Namek: Nameks are usually very shy creatures and very kind. Nameks have 2 attenees on their head. Some nameks are nice and some aren't like Slug. Nameks can fuse into another Namek, regenerate themselves, and pump up their muscles.
Majin: A Majin is an evil race who is controlled by Babidi. People like Majin Buu, Doubler, and others are Majins. You can tell if someone is a Majin if they have a M on their forehead.
Android: Androids are an artificial human who has unlimited power. They are very strong and are created by Dr.Gero
Changeling: Changeling are strong and evil creatures that can transform into stronger forms.
Arlian: Arlians are this bug type monsters that live on that Planet Arlia. They were killed by Vegeta and Nappa.
Kaioshin: Kaioshins are gods. They live on the Planet Kaioshin( You know the one Gohan was taken to take out the Z sword). Most of them were killed by Buu. They are prety strong.
Kaio: Kaios are Gods that live in the heavens. There are 4 Kaios. They were symbol on their backs representing them.
Saibamen: Saibamen are green aleins that are born by seeds from Nappa. They are really cool. But are really weak.