Doctor Strange could be a great helper. He has a deep understanding of the mystical arts and the multiverse. He might be able to see something in Peter's omega nature that others can't. Maybe he could use his magic to protect Peter from any threats that are related to his omega status or even help him control any new powers that come with it.
Definitely Tony Stark (if he were still alive in the fanfiction). Tony has always been a mentor to Peter. His vast knowledge and resources could be invaluable in helping Peter deal with whatever problem he has. He could create new gadgets for Peter to use in case his omega situation requires special equipment.
His Aunt May could also play an important role. She may not have superpowers, but she has always been a source of love and stability for Peter. She could offer him a safe place to stay and give him the emotional support he needs while he figures out what to do about his omega - related problems.
In a fanfiction scenario, it's also likely that he discovers a new community of omega superheroes or mutants. This new community could teach him about his omega nature, its strengths and weaknesses. They could also help him develop new skills or powers that are unique to omegas, which would then help him in his fight against evil.
Rocket could be another helper. With his technical expertise, he could build a device or figure out a scientific solution to bring back Peter's powers. He's always been good at tinkering with things.
His best friend Gerald would be a great character to assist Arnold. Gerald is often shown as confident and street - smart. He could use his charm and knowledge of the neighborhood to help Arnold out of whatever trouble he's in. For example, if Arnold is lost in a new part of town, Gerald could easily find their way back.
One common theme is identity struggle. Peter has to balance his identity as Spider - Man with his new - found omega identity. Another theme is relationship dynamics, especially with alphas in his life.
Maybe MJ. She could be in the area and use her quick thinking. She might find a large awning or something to break his fall, or she could call for help from nearby superheroes like Daredevil who could swing in and save Peter.
Aunt May is a very likely candidate. She has always been like a mother figure to Peter. She would notice that he's dirty or injured after a day of being Spider - Man and would gently lead him to the bathroom to get cleaned up. It would be a very nurturing moment between them, with Aunt May scolding him a bit for getting into so much trouble but also showing her love through taking care of him.
Fanfiction.net is also a good place to look. There are a large number of Spider - Man related fanfictions there. You may need to be a bit more specific in your search by adding keywords like 'omega' and 'Peter Parker' to narrow down the results.
One great 'Peter Parker Omega' fanfiction is 'Omega in the Spider-Verse'. It has an interesting take on Peter's omega abilities and how they interact with his role as Spider - Man. The story is filled with action - packed scenes and some great character development.
One popular omega Peter Parker fanfiction is 'The Omega's New Life'. It explores Peter's journey as an omega in a world that often misunderstands and challenges him. Another good one could be 'Peter Parker: Omega's Struggles', which delves deep into how he copes with his omega status while still being Spider - Man.
It could be a vengeful criminal that Spider - Man has put away in the past. This criminal has spent years in prison plotting his revenge and finally gets the chance when Peter is vulnerable. Maybe he manages to ambush Peter in an alleyway while he's on his way home from school or work.