Baby Saga:
Ten years after the end of DragonBall Z, Son Goku gets turned into a child again by a wish Pilaf made. The only way Son Goku can get back in his normal state is by finding the Black Star DragonBalls scattered across space. Son Goku, Pan, and Trunks go on journeys battling minor villans. At one planet, the DragonBall gang stumbles across Baby. Baby sneaks on board and lands on Earth. Baby takes over bodies in hope of finding a good host. Baby first uses Goten and Gohan as hosts, but he finally finds the most powerful host, it is Vegeta! Vegeta now turns into Baby-Vegeta. A great battle between Son Goku and Vegeta begins. It turns out Son Goku is no match for Baby-Vegeta. Then Kaiousin pulls out Son Goku's tail, hoping he can go into Oozaru stage. It works, but Son Goku still cannot defeat Bebi-Vegeta, who now is Super Bebi (Oozaru Bebi-Vegeta). Then something weird happens, Son Goku takes control of his body now and transforms into SSJ4 Son Goku! Son Goku soon defeats Super Bebi. (Note: Babi-Vegeta can also turn to SSJ4).

Super A 17 & Evil Shenlong Sagas:
In hell, Dr. Gero and Myuu creates Artifical 17. Artifical 17 comes from Hell to fuse with Android #17, when they fused, they became Super 17. Son Goku gets tricked into going to hell to fight Cell and Freeza, who was already dead. Without Son Goku, the earth is doomed. Piccolo, (who died in the Baby Saga) and Dende creates a portal so Son Goku can get out of hell. Son Goku later kills Super 17. When the DragonBalls are gathered to wish back the people killed in battle something goes wrong. Shenlong says that with all the negative energy the DragonBalls have restored, seven evil dragons have been formed. Each dragon possess a DragonBall, so Son Goku and the Z fighters go off to fight the evil dragons. When they come up agains Li, SSJ4 Son Goku fuses with... SSJ4 Vegeta! Making SSJ4 Gogeta. He beats the stuff out of him with ease. But Gogeta's fusion span was shortened because of the 4th stage of Super Saiyan. They can only stay fused for 20 min instead of 30 min. Just when Gogeta was about to finish Li, he diffuses. But the 2 warriors eventually killed the worn out Li. When all seven dragons have been defeated, the real Shenlong appears and grants Son Goku one wish, the wish is that everyone killed in battle against the dragons to be brought back to life. Shenlong tells Son Goku to get on his back, then the seven dragonballs are absorbed into Son Goku, and his whole body vanishes, leaving only his clothe on the ground. Seems that Son Goku is the most powerful fighter in the universe to have the DragonBalls absorbed.