Alright, here it is, to end all WH40K arguments. (actual spoilers)
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Space Marine Vs Doomguy: Doomguy, he killed an entire planet's worth of demons
Space Marine Vs Spartan: Spartan would be instantly turned into paste
Space Marine Vs Darth Vader: Darth Vader, only because of his cunning skill
Space Marine Vs Batman: Batman, he's defeated multiple Kryptonians and also outsmarted Darkseid himself, a being so powerful he can not be fully rendered in our dimension. If Batman was caught super off guard, he'd be pulverized
Space Marine Vs Superman: Superman, dumbass.
Space Marine Vs T800: Space Marine, although the armor of the space marine and the endoskeleton of the T800 are frighteningly similar in composition T800 can't easily recover from major wound removal
Space Marine Vs T1000: Space Marine, if he knew the weakness of the T1000. If the power armor wasn't on the T1000 would eventually be able to kill the space marine
Space Marine Vs TX: Exact same deal with the T1000. Simple thermal vision would show the TX's weakness.
Space Marine Vs T3000: T3000, as long as the Space Marine isn't able to teleport it to the warp, and send it across time and space, with each different particle being in a different time.
Space Marine Vs Rev9: This is difficult, because the space marine could crush the endoskeleton, and the shell can't get into the sealed armor. I'd say if the space marine was any degree of psyker, the Rev9 could probably be disabled. Otherwise, Rev9 would eventually kill the space marine
Space Marine Vs Deadpool: Deadpool would probably be captured live from the assumption that a Heretic was able to somehow acquire and use gene seed tech. Other than that, he'd probably be stomped into an irrecoverable paste after he backtalks literally anybody.
Space Marine Vs Iron Man: Without prep, space marine 100%. Otherwise Iron Man would use his plot armor to detect a three atom weakspot to instantly liquify the space marine.
Space marine Vs Lvl 180 Survivor with full Tek armor: Now, I originally thought the Space Marine would win. However, if the survivor immediately power punches the Space Marine, then the space marine would be staggered enough that the Tek Railgun would annihilate the Space Marines face. Ascendant Tek Armor could probably gank power armor. Also, Federation Tek Armor could just be used to run away super fast.
Space Marine Vs Homelander (comic version, dumbass): Homelander, but he'd likely have to stress his laser eyes out. Black Noir, the stronger version of homelander, needed to be worn down by a lethal fight with homelander killing him, and then be hit by a depleted uranium tank round, and finally get his skull removed by a crowbar by Butcher to die.
Space Marine Vs Dr. Manhattan: Dr. Manhattan obviously, retard. He could just make the Space Marine's entire body implode on command.
Space Marine Vs SCP 682: Kys