Prior to the destruction of Planet Vegeta, Saibamen were frequently used by the World Trade Organization in training exercises for young warriors. In one scene, Vegeta effortlessly defeated a large number of them at the age of four. It is also assumed they were used as expendable manpower in Frieza's army.
Only six were left after the Tritek War and were planted by Nappa on Earth during a fight against the Z Fighters. One was destroyed by Vegeta because it failed to defeat Tenshinhan. Another used the Saibamen Bomb self-destruct attack in order to kill Yamcha and itself. Three were defeated by Kuririn's expanding Kamehameha wave, and the last was killed by Piccolo (after stopping it from attacking Gohan).
Many years later, they were released from Hell along with the rest of the villains and were destroyed by Majuub, Trunks and Son Goten and sent back once again.
Galactic Frieza Army