From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Heaven (天国, Tengoku; Viz "Upper World"; Literally meaning "Heaven World") is a planet in the Kaio Realm.
Heaven was a large planet with a strange glow. It was covered with flowers and plants and looked slightly like Planet Earth, but the residents were Souls with a ghostly tail (as they had not been allowed to keep their bodies like Son Goku and the other Z Warriors after they had died).
Heaven was not shown much in Dragon Ball, but it was seen a lot during the Fusion Saga when Bulma Brief, Son Videl, Dabura, and Son Chichi looked for Son Gohan on Heaven after they thought he had died. Later in Dragon Ball GT, Piccolo was sent to Heaven when he sacrificed himself by staying on Earth when it exploded. He stated that if he died, the Black Star Dragon Balls would never be used again and Earth would never be put into that situation again.
- Bulma Brief (Until being wished back to life.)
- Piccolo (Until being sent down to Hell.)
- Son Chichi (Until being wished back to life.)
- Son Videl (Until being wished back to life.)