One interesting plotline could be Harry getting help from a secret magical society that has been hidden from the wizarding world. This society might have unique spells and knowledge that they share with Harry to defeat Voldemort.
In some 'Harry Potter Gets Help' fanfictions, Harry could get help from an unexpected character like a Muggle who has some sort of latent magical ability. For example, a Muggle with an uncanny ability to find magical objects. This could add a whole new dimension to the story as Harry has to work with someone who doesn't understand the wizarding world fully.
One possible plotline could be Harry finding new and unexpected allies outside of the wizarding world he once knew. Maybe he discovers a hidden community of magical beings who are shunned by the mainstream wizarding society and they take him in.
One interesting plotline could be that Harry wishes for the return of his parents. This would completely change the dynamic of the story. He would no longer be an orphan and would have a family to support him. It might also change his relationship with Dumbledore, as he wouldn't be as dependent on the headmaster. Another could be that he wishes for an end to Voldemort without having to fight. This would lead to a very different kind of resolution to the main conflict in the series.
In some fanfiction, Harry might get married in a secret ceremony to protect his family from a new threat. His friends would be the only ones in on the secret. The wedding could take place in a hidden location, like an ancient, enchanted forest. His wife could be a powerful witch who has her own secrets. Their marriage could be a key part of a bigger plan to defeat an emerging evil. There could be a lot of mystery and intrigue surrounding their relationship, with them having to keep their true feelings and intentions hidden from the outside world.
One interesting plotline could be Harry exploring the full extent of the Elder Wand's power without being corrupted by it. He might use it to restore parts of the wizarding world damaged during the war.
One plotline could be a Death Eater who was forced into Voldemort's service but secretly despises him. This Death Eater could start helping Harry by providing him with inside information about Voldemort's defenses. For example, they could tell Harry about the secret passages in the Death Eaters' lair.
One possible plotline could be that Susan Bones discovers some dark secrets about her own family that are related to Voldemort's rise. She then shares this information with Harry, and together they try to find a way to stop Voldemort from using these secrets to his advantage.
One possible plotline could be that Harry gets grounded for accidentally using magic outside of school in a Muggle area. This might lead to him having to deal with the disappointment of his friends who can't visit him as easily. Another could be that he gets grounded because he was caught sneaking out to follow a lead on a new dark wizard threat, and the adults in his life want to keep him safe by restricting his movements.
Some fanfictions might have Harry getting revenge on the Ministry of Magic for their incompetence and corruption. He could expose their wrongdoings to the wizarding public and bring about a new era of transparency and fairness in the magical government.
In this fanfiction, a possible plot point is that the goblins help Harry in a way that challenges the traditional wizarding world's rules. For example, they might introduce him to a different kind of magic that the wizards have long forgotten. Also, the goblins could have their own motives for helping Harry, like seeking a change in their status within the magical community. This creates an interesting dynamic as Harry has to navigate between his own goals and the goblins' interests.
Well, perhaps there could be a plotline where Loki, being a powerful and complex character, tries to use his magic to ensure the safety of Harry and the unborn child. He could be in conflict with other magical forces that see this as an abomination or a threat to the natural order. And Harry, on the other hand, might be dealing with his own insecurities and fears about becoming a parent at a young age.