Allow me to start off by explaining what the symbiote is, for those of you who may not know. It comes from a race of amorphous, extraterrestrial parasites. The parasites cover their hosts entirely, creating a symbiotic bond between the two, taking control of the hosts' mind. Spider-Man was the first to be corrupted by the symbiote, before he forced it off. Unfortunately, it found its way onto Eddie Brock, who became Venom after embracing the parasites that corrupted his mind. Other than these two, the suit has also attached itself to characters such as Cletus Cassidy (Carnage) and Flash Thompson. But who else do we know who has been enveloped by the parasitic symbiote?
1. Ms. Marvel (Carol Danvers)
Before becoming the beast you see in the picture above, Carol was the Avenger known as Ms. Marvel. During the events of Siege, Spider-Man confronts Venom about his sick behavior; eating squirrels, starting a gang war, and straight up eating people. During Spider-Man's battle with Venom, Ms. Marvel arrives and offers her assistance by pulling the human host, Mac Gargan, straight out of the symbiote. In response, the suit attached itself to Ms. Marvel, thus birthing She-Venom.
2. The Hulk
In a What If... comic What If The Alien Costume Had Possessed Spider-Man? Spidey has an encounter with the Hulk that ends with Hulk being possessed by the symbiote. One thing about the suit, is that the mind of the host can affect the symbiote, just as well as the symbiote can affect the mind of the host. That being said, the parasites didn't have to struggle to gain control over the Hulk's mind.
3. The Punisher
In another What If... story What If Venom Had Possessed The Punisher?, the vengeful Frank Castle gets ahold of the symbiote. The Punisher has his partner Microchip attempt to discover where the suit came from, while he gives the suit a field test. Punisher ends up discovering that it could not only shoot webbing, but bullets as well. With the suit, Castle began a more violent war on crime. The symbiote caused him to kill his partner Microchip, as well as beat Spider-Man within an inch of his life. Luckily for the web-head, Castle regained control, allowing Spider-Man to live.
During an outbreak of the Venom Symbiote Virus, several heroes were infected. One of those heroes was Wolverine. The Virus had a hard time possessing those with regenerative abilities, but it still got a hold of our favorite mutant. Eventually, Iron Man created an antidote that stopped the virus from spreading, and freed the hosts from their symbiotes.
This came from another What If... storyline where the merc with a mouth was possessed by the symbiote, thus birthing Venompool. Being part of Earth-90211, he is part of the same reality that the Beyonder loves to party in (that's right, the Beyonder likes to party), a reality that is also stuck in the 1980s in many ways. Venompool is also the Beyonder's go-to party animal, if you can believe it.
In What If The Alien Costume Had Possessed Spider-Man?, the symbiote takes ahold of the Hulk after his encounter with Spider-Man. The God of Thunder himself confronted Hulk/Venom and defeated the monster before the symbiote chose him as its next host. Thor was released from the symbiote's captivity after the Inhuman Black Bolt used his incredibly powerful voice to cause enough sonic damage to the suit.
7. May Parker
No, this isn't sweet old Aunt May. It's Peter Parker's daughter who was the Venom of Earth X. May Parker existed in Earth-9997 where she developed her abilities as a teenager, just like her father. After the symbiote bonded with May during unrevealed circumstances, May's strong, spider sense was able to subdue the symbiote, putting it under her control. She then took on the identity of Venom, and began her crime fighting career.