Bulma
Race: Human
Eyes: Purple
Hair: Purple
Abilities: Engineer, "Phee Phee"
Weapons: None
Series: DB, DBZ, DBGT
Bulma is the second character (after Goku) to be introduced into the Dragon Ball series. She hits Goku (and the fish he was carrying) while driving through the woods, searching for the mystical "Dragonballs." She eventually persuades Goku to come along with her, and thought that he would make a good bodyguard. Bulma has blue hair, and is the mother of Trunks. She is a genius with all sorts of electronics, alien and domestic.
Chi-Chi
Race: Human
Eyes: Black
Hair: Black
Abilities: Can control the most powerful men in the universe :)
Weapons: None
Series: DB, DBZ, DBGT
Chi-Chi is mother to Gohan and Goten and the spouse of Goku. She feels very strongly about Gohan's studies and will stop at nothing to get him to continue his work. Chi-Chi's father is the Ox-King. She mainly spends her time worrying about Gohan's academics. Chi-Chi is very uptight, but she makes a good story, and a good "Mom".
Gohan
Race: Half Saiyajin, Half Human
Eyes: Black
Hair: Black
Abilities: Bukujutsu, Kame Hame Ha, Masenko, Oozaru, Renzoku Energy Dan, SSJ, SSJ2, Zanzoken
Weapons: Zet Sword
Series: DBZ, DBGT
Son of Goku, he is trained by Piccolo to use his many hidden powers. He looks up to Piccolo for being such a great fighter, and is always trying to immitate him. Although he has the potential to become the most powerful being in the universe, he can be beaten because he cannot fully utilize his strength yet. Unlike Goku, his tail was never surgically removed, so he is still capable of turning into a Saiyajin under the light of a full moon.
Goku
Race: Saiyajin
Eyes: Black
Hair: Black
Abilities: Bukujutsu, Dragon Fist, Fusion, Genki-Dama, Jan-Ken Punch, Kaioken, Kame Hame Ha, Kiaiho, Oozaru, Renzoku Energy Dan, Shunkanido, SSJ, SSJ2, SSJ3, SSJ4, Taiyoken, Zanzoken
Weapons: Power-pole, Flying Nimbus
Series: DB, DBZ, DBGT
A Saiyajin from the planet Vegeta, he is sent to Earth as an infant so he can prepare it to be sold. Like all Saiyajins, he has the ability to change into a huge gorilla-like beast when there is a full moon. However, when he was young his tail falls out, and he is no longer able to change into the demonic creature. He could have easily eliminated all life on Earth, but he hit his head when he was young and forgot his mission. He now fights for the side of good, as the brainwashing had now been cured. Goku married Chi-Chi, daughter of Ox king; and together they had two sons, Gohan and Goten.
Goten
Race: Half Saiyajin, Half Human
Eyes: Black
Hair: Black
Abilities: Bukujutsu, Fusion, Kame Hame Ha, SSJ, Zanzoken
Weapons: None
Series: DBZ, DBGT
Goten is the second son of Goku and Chi-Chi. He and Trunks spend most of their time together, and are very good friends. Goten exhibited high power when he went Super Saiyajin at the age of seven. He bears a very strong resemblance of Goku. Goten has the same hair that Goku has, he also wears a miniture version of Goku's karate Gi. Goten is usually happy, but has a specialty for throwing tantrums to get something he wants.
Kami
Race: Namek
Eyes: Black
Hair: None
Abilities: Barrier, Bukujutsu, Create Dragonballs, Mafuba, Merging, Mystic Attack
Weapons: Staff
Series: DB, DBZ
Sent to planet Earth when his homeworld Namek was about to be hit by a comet, Kami-Sama created the Dragonballs on the planet. Kami is a genius and posesses great and mystical power. He wanted to be pure good and so he purged his evil and 'impure' side. Unfortunately, when this happened, his bad side became a new form, named Piccolo-Daimao. They have a spiritual link, so if one of the two dies, both of them die. As the guardian of Earth and creator of the Dragonballs on Earth, Kami plays a key role in the story.
Krillin
Race: Human
Eyes: Black
Hair: Black (Shaved)
Abilities: Bukujutsu, Double Tsuihikidan, Fusenko, Fusion, Kakusandan, Kame Hame Ha, Kienzan, Shishin No Ken, Taiyoken, Zanzoken
Weapons: None
Series: DB, DBZ, DBGT
Krillin is the most powerful human on Earth, although his power is still dwarfed by Goku and Gohan. He was once Goku's rival when they were young, but they later became best friends. He is a Buddhist monk, and shaves his head by choice. (He does grow some hair later in the series though) Krillin is willing to sacrifice his life for Earth, and whenever possible he is at Goku's side.
Mr.
Popo
Race: Genie
Eyes: Black
Hair: Unknown
Abilities: Flying Carpet
Weapons: None
Series: DB, DBZ, DBGT
Mr. Popo is Kami's best friend and assistant. He is also a powerful fighter. He wears a white turban with an oval shaped gem in the center, and travels sometimes by means of flying carpet or teleportation. Mr. Popo does not look very much like a human, more like an inflatable balloon in the shape of a human.
Oolong
Race: Pig
Eyes: Black
Hair: None
Abilities: Shape-shifting
Weapons: None
Series: DB, DBZ, DBGT
Though he may change into any form he wishes he can't really fight in any form. It's because he doesn't aquire any special skills into what he's transforming into. Another thing is that he can't stay tranformed for more than five minutes or his muscles get tired and he reverts back into his pig form. In a fight Oolong is more of a spectator than help, he is considered a coward. He's also a quite a pervert, always trying to get a peek at a woman, especially Bulma.
Ox-King
Race: Human
Eyes: Black
Hair: Black
Abilities: None
Weapons: None
Series: DB, DBZ, DBGT
The Ox-King appears here and there throughout the series. His first appearance is back in Dragonball. Ox-King knows Roshi because he trains with Gohan (Goku's Foster Grandfather) when he is still a pupil of his. He says that they always competing with each other. Ox-King occasionally pops up during the series but not that much. Usually we'll see him getting verbally abused by his own daughter.