Please note: This is my own view of what I think would happen if Doomsday went up against random people, random universes, like boss battles, so don't judge me. Let me be free and write what I want, but feel free to express your opinion on how accurate I was for the battles and opponents I selected.
Battle 1: Joker, Harley Quinn, and their Henchmen (including Mr. Hammer)
In the Joker's base. He takes out the thugs, especially the Titan thugs.
Joker: Harley, we better put in maximum effort, especially with Mr. Hammer helping us.
Harley surprises Doomsday with a machine gun and exploding pie attack, but it fails. He takes out Mr. Hammer with one punch
Harley: Oh, no. He's more dangerous than Batman
Joker throws a crowbar, fires his guns and uses his buzzer, but they all fail.
Joker: Harley, blow up this building, it might work
Harley presses the detonate button, but Doomsday is still alive and kills both of them
Battle 2: Hulk and Vertigo
Vertigo makes Doomsday vomit, but he gets payback and kills her
Hulk goes in, and they punch each other. He wacks Doomsday with a car. Hulk then pulls the sonic clap, but in the middle of it, gets punched by Doomsday. Doomsday knocks down one of the buildings, but Hulk goes world breaker, punching Doomsday multiple times, stepping on his leg, but it grows back, and Doomsday stabs Hulk, and pulls out his head.
Battle 3: Wolverine
The battle is in New York City at knight.
The 2 show up and the fight begins. Wolverine throws a steel beam, whacking Doomsday in the face. Wolverine runs up and stabs Doomsday in the leg. Doomsday throws him at a car, but Wolverine regenerates. Doomsday steps on his chest, but this distracts him, allowing Wolverine to stab him in the leg, and slashing him in the eye. Doomsday decides to finish this, and Wolverine goes beserker, and Doomsday slashes Wolverine and throws him upwards, then punches him as he falls down.
Battle 3: Iron man
Tony fires his blasts, and missiles, but no damage. He decides to switch to the Hulkbuster, which does at least a little damage. However, the batteries die. He goes to the Ultra suit, controlled by alien parasites. It does more damage to Doomsday than Wolverine's claws, but Doomsday grabs him by the leg and beats him up.
Battle 4: Ben Tennyson (Ultimate Alien style, but with all future Aliens and the combo aliens from that one episode)
The battle is in Bellwood, at night. Ben turns into Swampfire, but the methane, fire, and seeds have no effect. He goes Ultimate, but still no effect. He decides to turn into Echo Echo, then Ultimate. It gives Doomsday, a migraine. He turns into Brainstorm, and the scanner shows he has no brain, so he turns into Water Hazard, fires water, then into Ampfibian, injuring Doomsday, then into Nanomech, firing him in the eye. He then turns into Clockwork to slow Doomsday, and hurt him. He then turns into Chamalien, camouflages and stabs him with his tail. After that, he goes into Ghostfreak, to possess him into punching himself multiple times.
Ben: Take, that.
But Doomsday gets back up and throws Ben all the way towards the other side of America
Battle 5: Predator
In the Colombian rainforest, Predator fires at a log, Doomsday is standing on. He continues to fire, until he beats up Predator, and survives the bomb.
Battle 6: Hela
Doomsday meets Hela. Hela runs up to him, and punches him 20 times, and then teleports him from a mountain, and punches him off.
Doomsday: You're tough, but can you defeat me.
Hela: Stay down!
Hela continues to beat him up, and twists his leg with her Magic, but he regenerates and beats her up, winning.
Battle 7: Silver Surfer
Doomsday: A silver human. Easy
Silver Surfer: Don't underestimate
Doomsday runs toward the Surfer, but the Surfer blasts him 50 feet forward, giving him a headache, then kicks him in the crotch, but Doomsday gets back up. Silver Surfer then twists his neck, and his leg, but Doomsday beats him up, kicking his crotch, and the poison, doing no effect.
Battle 8: Gladiator
A battle on the moon
Gladiator reaches maximum confidence. He flies and punches Doomsday, launching him and he gets hit by a meteor, and then blasts him with the heat beams and super breath. His microscopic vision shows his impossible immortality, so he decides to punch him at maximum energy and speed, but Doomsday poisons him, and wins.
Battle 9: Kratos
Kratos: I've defeated gods! Get ready to lose
Kratos stabs Doomsday in the back with the blades of Athena, and uses the bow of Apollo. It does hardly any damage, so he uses the Nemean gauntlets, and the claws of Hades. As a last resort, he uses the blade of Olympus, which makes Doomsday vomit, and trip, but he grabs Kratos, and makes him bleed.