Wikia

Age 774 is a major year in the Dragon Ball universe. It is this year that every event between the World Tournament Saga and Kid Buu Saga take place.

Broly is killed (movie only)
The 25th World Martial Arts Tournament takes place on May 7th.
Goku is allowed to come back to Earth for a day to compete in the tournament.
Spopovich, Yamu, Pui Pui, Yakon, Dabura, and Babidi are all defeated and killed.
Majin Buu is reborn.
A clone of Broly is created, Bio-Broly, and is later destroyed (movie only).
Saike Demon transforms into Janemba, later turns into Super Janemba. This happens on Saturday, the 16th (movie only).
Goku and Vegeta use the Fusion Dance for the first time, forming Gogeta (movie only).
Old Kai is freed from the Z Sword.
Van Zant and Smitty go out on a murder spree.
Majin Buu creates Evil Buu, who absorbs Majin Buu and becomes Super Buu.
Super Buu launches the Human Extinction Attack, killing most people on Earth, and he absorbs Gotenks and Piccolo, and later Gohan.
Old Kai gives his life to Goku.
Vegeta and Goku fuse to form Vegito.
Kid Buu blows up planet Earth using his Planet Burst technique.
Everyone killed by Majin Buu is revived (except those who are evil).
Goku uses the Super Spirit Bomb to kill Kid Buu.
Kid Buu is reincarnated into Uub.
Hirudegarn terrorized the Earth and was killed by Goku's Dragon Fist (movie only).
Tapion used the Time Machine to return to his time and his planet (movie only).

Age 774