Here, I'll be doing a list of Death Battles that I have done before, and will do in the future. I will also be showing who won the Death Battle that has been published, so spoilers ahead.
(Season 1)
Hamister VS Goater (OC battle) Winner: Hamister
Fox VS Hazel (Animals of Farthing Wood VS Watership Down) Winner: Fox
Skunk VS Po (Skunk Fu VS Kung Fu Panda) Winner: Po
Plankton VS Dr Kamikaze (SpongeBob VS Robotboy) Winner: Dr Kamikaze
Pokémon Johto Starter Battle Royale (Meganium VS Feraligatr VS Typhlosion) Winner:
Hugo & Rita VS Dylan & Dolly (Jungledyret Hugo VS 101 Dalmatian Street) Winners: Hugo & Rita
Alex Mason VS Franklin Clinton (Call of Duty VS Grand Theft Auto) Winner: Franklin
Johnny Bravo VS Glenn Quagmire (Cartoon Network VS Family Guy) Winner: Johnny Bravo
(Season 2)
Johnny Bravo VS Pepe le Pew (Cartoon Network VS Looney Tunes) Winner: Johnny & Pepe (they became friends)
Scrooge McDuck VS Mr Krabs (Ducktales VS SpongeBob) Winner: Scrooge McDuck
Shao Kahn VS King Dedede (Mortal Kombat VS Kirby) Winner: King Dedede
Hector Con Carne VS Dr Doofenshmirtz (Evil Con Carne VS Phineas & Ferb) Winner: Hector Con Carne
Ferra & Torr VS Haztim & Hustimb (Mortal Kombat VS OC) Winners: Haztim & Hustimb
Cool Cat VS Ghost Rider (Cool Cat Saves the Kids VS Marvel) Winner: Ghost Rider
Buster Bunny VS Robin (Tiny Toon Adventures VS Teen Titans Go) Winner: Buster Bunny
Mac Track'em VS King Rexton (OC battle) Winner: King Rexton
(Season 3)
General Grievous VS Machamp (Star Wars VS Pokémon) Winner: Machamp
Hugo & Rita VS Humphrey & Kate (Jungldyret Hugo VS Alpha & Omega) Winners: Hugo & Rita
Hamister VS Joker (OC VS Persona 5) Winner: Joker
Samurai Jack VS Silver Samurai (Cartoon Network VS Marvel) Winner: Samurai Jack
Gene VS Rambo (The Emoji Movie VS the Rambo movies) Winner: Rambo
Captain Falcon VS Red Ranger Jason (F-Zero VS Power Rangers) Winner: Captain Falcon
Angry Video Game Nerd VS Twilight Sparkle (Cinemassacre VS My Little Pony: Friendship Is Magic) Winner: Angry Video Game Nerd
Sub-Zero VS Ice King (Mortal Kombat VS Adventure Time) Winner: Sub-Zero
Zack & Marie (Riolu & Eevee from Explorers of Sky) VS Charlie & Charlotte (Charmander & Chikorita from Super Mystery Dungeon)
Hulk VS Blanka (Marvel VS Street Fighter)
Shredder VS Afro Samurai (Teenage Mutant Ninja Turtles VS the Afro Samurai series)
Dudley VS Little Mac (Street Fighter VS Punch-Out)
Mickey Mouse VS Bugs Bunny (Disney VS Looney Tunes)
(Season 4)
Joker & Morgana VS Banjo & Kazooie (Persona 5 VS Microsoft)
MetaKnight VS Nightmare (Kirby VS Soul Calibur)
Plankton VS Ursula (SpongeBob VS The Little Mermaid)
Killer Croc VS King K Rool (DC VS Nintendo)
Ganondorf VS Sephiroth (Legend of Zelda VS Final Fantasy)
King Rexton VS Father (OC VS Codename: Kids Next Door)
Finn the Human VS Steve (Adventure Time VS Minecraft)
M. Bison VS Bowser (Street Fighter VS Nintendo)
Pikachu VS Agumon (Pokémon VS Digimon)
Ruby Rose VS Sora (RWBY VS Kingdom Hearts)
Sandy Cheeks VS Slappy Squirrel (SpongeBob VS Animaniacs)
Dracula VS Doomsday (Castlevania VS DC)
The ones that don't say who won them is because those battles haven't been made yet. RedHood123, let me know your predicted winners for season 4, as well as your favourite matchup from each season.