Despite the lack of Spider-Man, Venom is still including a fair amounts of elements from the character’s comic book history.
It’s also rumored that Woody Harrelson, who is only in “a little fraction” of Venom, is playing Cletus Kasady, better known in the comics as Carnage.
Assuming this Carnage information is true, then should Venom be a commercial success, then it sounds like we would see Eddie and Cletus duke it out in Venom 2.
Alas, barring any future changes, it doesn’t look like Spider-Man will have any role to play in these particular shenanigans, but it’s okay.