Dragon Ball: All of Goku’s Zenkai Boosts, In Chronological Order

Akira Toriyama introduced Zenkai Boosts during Dragon Ball Z‘s Frieza Saga as a means to help Goku, Vegeta, and Gohan get stronger in a setting where they wouldn’t be able to train long enough for natural power-ups. When Krillin learns that Saiyans experience Zenkai Boosts after surviving life or death battles, he comments that Goku always got stronger after his fiercest battles during the original Dragon Ball.