Gohan
When Fat Majin Buu destroyed the Earth
In the Future Trunks' timeline, he was killed by the Androids

Vegeta
Against Freeza
Against Majin Buu
In Future Trunks' timeline, he was killed by Android 17

Piccolo
Against Nappa
When Fat Majin Buu destroyed the Earth
In Future Trunks' timeline, he was killed by the Androids
When the Earth explodes in DBGT and he refuses to leave the Earth that he loves so much

Krillin
Against Tambourine
Against Freeza
Turned into chocolate and eaten by Majin Buu
killed by Android 17 in DBGT
In Future Trunks' timeline, he was killed by the Androids

Trunks
When Fat Majin Buu destroyed the Earth

Goten
When Fat Majin Buu destroyed the Earth

Yamcha
Saibamen exploded on him
Eaten by Majin Buu

Chao-Zu
Against Piccolo Daimoah
Sacrificed himself to try and kill Nappa
When Fat Majin Buu destroyed the Earth

Tien
Suicidal Blast against Nappa
When Fat Majin Buu destroyed the Earth

Babidi
Killed by Majin Buu