She could also provide Harry with some protection. In fanfiction, she might be even more proactive in keeping Harry safe from the dark forces. For example, she could give him a magical charm or a secret spell that only she knows to fend off enemies. Or she could arrange for some trusted allies to keep an eye on Harry when she can't be around.
One possibility is that Voldemort could initially be amused by Harry's request. He might toy with Harry, pretending to consider helping while actually having his own evil plans. For example, he could use Harry's vulnerability at that moment to gain some sort of advantage, like getting information about the Order of the Phoenix. Or, Voldemort could see it as an opportunity to corrupt Harry further, slowly turning him to the dark side by making false promises of power and protection.
He could be in a situation where he's trapped in the Ghost Zone. His friends might have to figure out a way to get to him. They could use some of Tucker's new inventions, like a Ghost Zone - traversing vehicle. They'd face many challenges along the way, such as avoiding other dangerous ghosts.
If Harry Potter gets help from the Queen in fanfiction, the Queen could offer her strategic wisdom. Given her experience in ruling and dealing with various threats, she could help Harry plan his battles against Voldemort. She might also introduce Harry to a network of powerful Muggles who could support his cause in different ways, like providing financial aid for the Order of the Phoenix or helping to spread anti - Voldemort propaganda among Muggles.
Well, in such a fanfiction, perhaps the Death Eater could initially be reluctant to help Hermione. But if there's some common goal, like stopping a greater evil in the wizarding world that might affect both the good and the Death Eaters' side, they could form an uneasy alliance. For example, a powerful dark magic artifact is about to be misused by a new dark wizard and Hermione realizes she needs the inside knowledge of the Death Eaters to stop it.
Well, in this kind of fanfiction, Harry might receive some sort of otherworldly knowledge or power from Death. Maybe Death gives him the ability to see the true nature of dark magic, which helps him in his fight against Voldemort. It could also be that Death shows Harry the fates of different characters, guiding his actions to ensure the best outcome for the wizarding world.
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.
In the fanfiction, Snape could be in a really tough situation when Harry comes to him for help. On one hand, he has his loyalty to the Dark Lord (or at least that's what others think), and on the other, there's this boy who is the son of the woman he loved. He might end up guiding Harry in a very roundabout way, like giving him a potion ingredient that has a hidden meaning or leading him to a certain book in the library that contains the solution to Harry's problem.
I recommend the book, Guide to the Male Lead. The protagonist Shu Xin transmigrated to a different plane world and needed to win the favor of the supporting male, the male cannon fodder, and the male protagonist. This book meets your needs, and it specifically tells the story of the female supporting character's counterattack. I hope you will like this recommendation. Muah ~