Killed by Piccolo in order to assure the death of Raditz in the begining of the Z series.

Killed by Cell

Killed in the Alternate timeline (Future Trunks' Time) from a heart disease.

Piccolo is killed by Napa

Yamcha is killed by one of the Saibamen

Choazu sacrifices himself to try to stop Napa

Tien is killed by Napa

A bunch of humans

Krillin, right before Goku goes SSJ1 for the first time.

Dende, right after Frieza changed into 4th Form

Vegeta right after Goku finally arrives from the healing tanks

Lots of Nameks

All but a few  Saiyans

Goku dies when Cell Self destructs

King Kaioh, but it was partly Goku's fault

Gohan is killed when Buu destroyed the Earth

Vegeta is killed by Majin Buu

Piccolo, Krillin, Trunks, Goten, Choazu, Tien all killed when Buu destroys the earth

Yamcha was eaten by Majin Buu

Babidi is killed by Majin buu

Vegeta kills Napa for his incompetence

Vegeta kills Dodoria, Zarbon, Cooey, and the Ginyu Force.

Gohan kills Cell

Goku kills Frieza

Future Trunks kills Frieza-bot and King Cold.

Goku kills Piccolo-Diamoah