Here is a death list of characters that have been killed and how they got killed.

Dark Blue: Good Guy
Light Blue: Bad Guy
(Green): Kill Count

Android #16
- Head stepped on by Cell

Android #17 (1)
- When Cell self-destructs
- Killed by Trunks in future timeline

Android #18 (1)
- Killed by Trunks in future timeline

Android #19
- Destroyed from Vegeta's Big Bang Attack
- Killed by Trunks in GT

Android #20 (Dr. Gero) (1)
- Head stepped on by Android #17
- Skull is crushed in the Trunks timeline
- Killed by Super #17 under Dr. Miyu's control

Burter (Ginyu Force)
- When his neck is snapped by Vegeta's knee

Babidi (1)
- Head blown off by Fat Buu

Bardock (1,000+)
- When Frieza shoots a massive energy ball at Planet Vegeta

Bebi (1)
- Killed by SSJ4 Goku

Bibidi
- Killed by the East Kaioshin

Black Sousei (1)
- Killed by Goku and Android #8

Blue Shogun
- Killed by Tao Pie-Pie

Bubbles
- When Cell self-destructs on King Kai's Planet

Bulma
- Turned into chocolate and eaten by Super Buu

Cell (1,000,000+)
- Blasted apart by Gohan's Kame Hame Ha
- Killed by Trunks when he returns to the future

Cell Jr
- Got their ass kicked  by SSJ2 Gohan

Chiaotzu
- Blown away by Piccolo Daimao
- When he self-destructs in an attempt to kill Nappa
- When the Earth was blown up by Kid Buu
- Killed by Android in future timeline

Chi-Chi
- Smashed by Super Buu after being turned into an egg

Dabura (1)
- Turned into a cookie by Fat Buu

Dende
- Killed by Frieza on Namek

Dodoria (10+)
- Melted by Vegeta's attack

Drum
- Decapitated by Goku

Frieza (1,000,000+)
- Got screwed up by Trunks
- Killed by Goku in Mirai Trunks' timline

Garlic
- Destroyed by Kami-sama

Guldo (Ginyu Force)
- Decapitated by Vegeta

Gohan (12)
- When Kid Buu blew up the Earth
- Was killed by Android in Trunk's timeline

Gohan (Grandfather)
- Stepped on by Oozaru Goku

Goku (100+)
- Sacrificed his life to save the world from Radditz
- Got blown up along with Cell as he was getting ready to self-destruct
- Died of heat disease in Future Trunk's timeline

Goten
- When Kid Buu blew up the Earth

Gregory
- When Cell self-destructs on King Kai's planet

Guru
- Dies Namek (Stress)
- Dies on Earth (Natural)

Jeice (Ginyu Force)
- Vaporized by Vegeta

Kami (1)
- Dies when Nappa fries Piccolo
- Dies with Piccolo in Trunk's timeline

Korin
- When Kid Buu blew up the Earth

Kibit
- Beheaded by Dabura

Kid Buu (1,000,000,000+)
- Vaporized by Goku's Genki-dama

King Cold
- Blasted by Trunks
- Killed by Goku in Mirai Trunks' timeline

King Kai
- When Cell self-destructs on King Kai's planet

Krillin
- Killed by Tambourine, one of Piccolo Daimao's minions
- Killed by Frieza
- Turned into chocolate and eaten by Super Buu
- Killed by Android #17 in DBGT
- Killed by Android in Future Trunk's timeline

Kuwi
- When Vegeta puffs him up like a balloon and explodes him

Master Roshi (3)
- Died trying the Mafuba attack on Piccolo Daimao
- Eaten by Super Buu after being turned into chocolate

Mustard (Spice Boys')
- Killed by Gohan

Namu
- Killed by Tambourine

Nappa (1000+)
- Killed by Vegeta
- Killed by Vegeta in GT

Oolong
- Eaten by Super Buu after being turned into chocolate

OxKing (Gyuu Mao) (10+)
- Eaten by Super Buu after being turned into chocolate

Piccolo (2)
- Killed while protecting Gohan from Nappa
- When Buu blew up the Earth
- When the Earth explodes in DBGT and he refuses to leave the Earth that he loves so much
- Killed by Android in Future Trunk's timeline

Piccolo Daimao (1,000+)
- When Goku rips through his chest with a flying head butt

Mr. Popo
- Eaten by Buu

Puar
- Eaten by Super Buu after being turned into chocolate

Pui Pui (1)
- Killed by Vegeta

Radditz (100+)
- Blasted by Piccolo's Makankosappo

Red Ribbon Army
- Wiped out by Goku

Recoome (Ginyu Force)
- When he is blasted by Vegeta

Grand Kai (Dai Kaio)
- When he offers his life to Goku

Salt (Spice Boys')
- Killed by Gohan

Spice (Spice Boys')
- Killed by Gohan

Super #17 (1)
- Destroyed by Goku and Android #18

Tambourine (3)
- Killed by Goku

Tao Pie-Pie (2)
- When his own grenade is kicked back to him

Tien (Tenshinhan) (1)
- Killed himself with a Kikouhou when trying to destroy Nappa
- When Buu blew up the Earth
- Killed by Android in Future Trunk's timeline

Tomar
- Killed by Dodoria

Toteppo
- Killed by Dodoria

Trunks (10+)
- When Cell shoots through his chest
- Killed in Cell's timeline
- When Buu blew up the Earth

Ubuu
- Accidentally turns himself into chocolate, eaten by Bebi Vegeta

Vegeta (100,000+)
- When Frieza kills him on Namek
- When he sacrifices his life to destroy Buu
- Killed by Android in Future Trunk's timeline

Videl
- Turned into chocolate and eaten by Super Buu

Vinegar (Spice Boys')
- Killed by Gohan

Yajirobe (1)
- When Kid Buu blew up the Earth
- In Future Trunks' timeline, he was killed by the Androids

Yakon
- Overwhelmed by Goku's Ki

Yamcha
- When a Saibaman self-destructs
- Turned into chocolate and eaten by Super Buu
- Killed by Android in Future Trunk's timeline

Zarbon (10)
- Destroyed by Vegeta