The Green Goblin is often a common antagonist. His chaotic nature and vendetta against Spider - Man would still be a major threat even if Peter is reborn. He might come up with new and more devious plans to take down Spider - Man.
Doctor Octopus is another one. His brilliant mind and mechanical tentacles make him a formidable foe. In a reborn Peter Parker story, he could be even more determined to prove his superiority over Spider - Man, perhaps seeing Peter's rebirth as an opportunity to finally defeat him once and for all.
Venom is also frequently seen as an antagonist. The alien symbiote's hatred for Spider - Man would not change just because Peter is reborn. Venom could be more aggressive and unpredictable in this kind of fanfiction, making it a real challenge for Peter to deal with him.
One of the common antagonists could be Hydra agents. Since Steve has a long history with Hydra, it makes sense for them to be a threat in these fanfictions. They might be trying to steal some new technology that Peter has access to, or they could be after Steve again. Another antagonist could be some of Spider - Man's classic villains like the Green Goblin or Doctor Octopus. They might team up with other villains or forces to take on Steve and Peter together.
In this fanfiction, it's possible that a symbiote - influenced villain could be the antagonist. Maybe someone who has bonded with a part of the symbiote and has a thirst for chaos. They might see Flash as an easy target to cause mayhem and draw out Spider - Man. Additionally, the Scorpion could be another antagonist. He might be hired by some shadowy figure to capture Flash in order to lure Spider - Man into a trap. There could also be a group of alien invaders who mistake Flash for someone important and Peter has to save him from their clutches.
A new and original antagonist could be a rogue psychologist who has developed a powerful hypnosis technique. This character might be jealous of Peter's abilities and want to use hypnosis to take over his mind and use his powers for their own gain. Or it could be a secret organization that wants to use Peter as a weapon, and they use hypnosis as a means of control.
Often, other symbiotes can be the main antagonists. For instance, Venom himself might see Anti - Venom (Peter) as a threat and constantly try to attack him. Venom could be jealous of the power that Anti - Venom has or simply view Peter as an enemy because of the different nature of their symbiotic relationships.
The Green Goblin could be a main antagonist. He's known for causing chaos in New York City, and a building collapse would be right up his alley. He could be targeting the building for some strategic reason, like trying to get to Peter Parker or to create general mayhem.
Maybe it's a group of intergalactic criminals who are after the power that Peter Parker has as a 'child of the universe'. They could be stealing artifacts from different planets to gain more power and they see Peter as the ultimate source of power that they need to complete their collection.
The Green Goblin could be a main antagonist. He might see Peter's control of Alchemax as a threat to his own criminal empire and try to take over the company or destroy it. Another could be Doctor Octopus. With his brilliant mind, he may want to use Alchemax's resources for his own mad experiments.
One possible antagonist could be a new super - villain who has a grudge against Peter Parker and targets his school to get to him.
Mary Jane Watson is often a common character. She might be Peter's love interest and support system as he navigates the complex Web of Life. Another one could be Aunt May, who provides the home - like and moral support to Peter. Also, villains like Doctor Octopus or Green Goblin can appear, as they often cross paths with Peter in his adventures related to the Web of Life.
One of the most common characters is Ned Leeds. He could be Peter's gym buddy, always there to spot him or give him some friendly advice. Another would be MJ. She might show up at the gym to check on Peter or even join in on the workouts. Flash Thompson could also be a character in these fanfictions. Maybe he challenges Peter to a friendly competition at the gym.