
The one star dragon ball.
Earth Dragon Balls.
If one gathers all seven dragon ball's then they can summon the eternal dragon, Shenron and grant a single wish within the dragons power, however one must know the right password to summon the dragon or nothing will happen. Once they have been used they cannot be used for another year.

A Namekian Dragon Ball.

The Dragon Radar, indicating the positions of the seven dragon balls.
As a youth Bulma created a radar that tracks Dragon Balls, which have been of great use to the Z fighters as it would take a very long time to track them without it.