Warning: SPOILERS Below For Venom!
Spider-Man may not exist in , the cover of Detective Comics #27 (the first appearance of Batman) can be seen on a wall as the first Nite-Owl punches out a thug, signifying that a movie superhero universe can also have other famous superheroes existing, but as fictional characters. However, Watchmen and DC’s heroes are all owned by Warner Bros.; Sony’s Venom referenced a competitor studio’s character, albeit indirectly.
There’s also a second, even subtler reference to Superman in Venom: In the final battle between Eddie/Venom and Carlton Drake, who is possessed by the evil symbiote called Riot, Eddie performs a running jump into a punch onto the villain. That move is called a Superman Punch, made famous by WWE wrestler Roman Reigns. So even though the symbiote antihero successfully establishes his own franchise without Spider-Man, it’s Superman who inadvertently looms large over Venom.