The Venom movie might not be attached to the Marvel Cinematic Universe, but that doesn't mean there aren't plans for the franchise to continue after the first film is over. Director Ruben Fleischer admits that Venom does lay the groundwork for a potential sequel, though, obviously, whether or not we see that sequel is dependent on how successful Venom is. According to Fleischer...
We've definitely laid some groundwork for different directions that the franchise could go but obviously it all hinges on people's excitement about this film. I hope people will stay and see what seeds have been planted.
It will be interesting to see just how seeds will be planted for potential Venom sequels because the Venom origin story here is so different from what is traditionally told, due to the fact that there is no Spider-Man. Therefore, any follow-up stories will likely also be taking a very different tact. We could be introduced to characters in Venom who could turn out to be important in a sequel but in ways completely unexpected simply because sequels will be based on this version of Venom.
Interestingly, Ruber Fleischer also tells Comicbook.com that he hopes people will "stay" and see what seeds have been planted, which implies that the sequel set-up work could all be done in a post-credits sequence, or more than one, that fans will have to wait through the credits to see. While Venom may not be an MCU movie there's no reason they can't take a page from Marvel's book that has proven incredibly successful, keeping fans around to get a small tease of what's to come.
One also has to wonder if a post-credits sequence in Venom could lay the groundwork for more than just a sequel. We know that Sony is working on several projects using characters from the Spider-Man comics, including a Black Cat/Silver Sable team up and a Morbius: The Living Vampire movie that will apparently star Jared Leto. While it may be a bit early to start teasing those films, you never know. Iron Man started setting up the Avengers when little about the MCU was a sure thing. If Venom is the start of its own film universe, and Sony knows where they want to go with it, we could see the first hints of that here.
Of course, it all depends on how Venom does financially. While it's too early to estimate how an October film will do at the box office, Venom certainly has the name recognition that will help. The character is extremely popular, which is why Sony moved this project forward first. October is a somewhat unusual time to see a comic book project released, but that also means Venom will have little similar competition. The film is certainly doing what it can to ensure success, which means we may see those sequels down the road.