Another idea is that after Snape sacrifices himself, his spirit somehow remains bound to Harry. He becomes a sort of spiritual guide for Harry, like a father figure from beyond the grave. Harry has to learn to communicate with Snape's spirit and in the process, they heal old wounds and form a deep bond.
A plot could be where a rare and endangered creature chooses Harry and Snape as its protectors. They must travel to different magical locations to find a safe haven for it. This would force them to interact and rely on each other's skills.
One interesting plotline could be Harry growing up with Snape's guidance and inheriting his potions skills at an early age. He might have a different dynamic with the other Hogwarts students, being more of an outcast due to his connection to the often - misunderstood Snape.
One idea could be a story where Harry, under the influence of a powerful spell, has to live a day in Severus Snape's memories. He gets to see Snape's childhood, his unrequited love for Lily, and all the sacrifices he made. This would give Harry a new perspective on Snape.
One way it could be possible is through a magical spell gone wrong. Maybe a time - traveling spell that alters their relationship. In this fanfiction, Snape could discover he has a connection to Harry that he never knew before, and his protective instincts grow even stronger.
One idea could be that Harry discovers the truth about his parentage early on. This changes his relationship with Dumbledore as he realizes Dumbledore had been keeping this big secret from him. He might also struggle with his identity, feeling torn between the Gryffindor ideals he was raised with and the Slytherin traits he might inherit from Snape.
Yes, in certain fanfictions. Fan writers like to play with the established relationships in the original 'Harry Potter' series. They might decide to make Harry Snape's son to add a new layer of drama and mystery. For example, it could change the way we view Snape's actions throughout the series, as his protectiveness towards Harry could then be seen as a fatherly instinct.
One idea could be that Snape takes Harry in secretly. He teaches Harry advanced potions and magic in a more personal way, away from the prying eyes of Hogwarts. Harry begins to see Snape in a new light, not as the mean professor but as a strict yet caring guardian.
One idea could be that in the fanfiction, the collar is a magical device used for protection rather than a form of control. Snape might put it on Harry to shield him from dark magic threats at Hogwarts.
There are many fanfictions that explore Severus Snape's father. Some might depict him as a cruel man who had a negative impact on Snape's childhood. In some fanfictions, he could be an absent figure, which might have contributed to Snape's rather solitary and often bitter nature.
In some fanfictions, Severus Snape being Harry Potter's father is a radical but interesting concept. It often involves re - imagining the relationship between Lily and Snape. Maybe there was a hidden, deeper connection between them that led to Harry's birth. This changes the whole dynamic of the story as Snape would then have a more personal stake in Harry's life from the start.