You can start by looking on fanfiction.net. It has a large collection of Harry Potter fan fictions, and there are likely quite a few 'Snape adopts Harry' ones in there. Just use the search function and type in the relevant keywords.
In this fan fiction, Snape's character development is quite remarkable. At first, he might be hesitant and conflicted about saving and adopting Harry. But as time goes on, he becomes more selfless. He has to learn to communicate better with Harry, which is a big change for him. He also has to face his own demons from the past, like his relationship with James Potter. This journey of self - discovery and growth makes his character more three - dimensional and likable in the context of the fan - made story.
One big challenge is their pre - existing relationship. They've had a lot of conflicts in school. Snape has been rather harsh on Harry, so they need to overcome that animosity. Also, Snape has to deal with Harry's trauma from the Dursleys. He needs to help Harry heal and grow in a positive way, which is not easy for someone as emotionally reserved as Snape.
You can start by looking on fan - fiction websites like Archive of Our Own (AO3). It has a large collection of fan fictions, and you can simply search for 'Severus Snape rebirth' in the search bar. There are usually tags and filters that can help you narrow down your search to the specific type of story you want.
In this fan fiction, Snape might adopt Harry because he realizes that Harry has a lot of potential that is being stifled at the Dursleys. He could take Harry to a secret location and train him not only in magic but also in self - defense and survival skills. Snape would have to deal with his own complex feelings towards Harry, as he has both resentment and a sense of obligation. And Harry would have to adjust to living with Snape, who is not exactly the warmest person. It could be a story of growth and understanding between the two.
In this fan fiction, Snape could save Harry from Voldemort's followers who are after him. The blood adoption might be a way to give Harry a new family connection. Snape, having complex feelings for Harry's mother, might see this as a way to fulfill a promise or a way to atone for past actions. He could then teach Harry some of his more advanced potions knowledge and help him develop his occlumency skills better.
In this fan fiction, Snape's character development could be quite complex. Saving Harry is just the starting point. With the blood adoption, he is thrust into a new role. He may initially struggle with this new identity as a sort of surrogate father. However, as time passes, he could learn to love Harry in his own way. His development might also involve him reconciling his past actions, especially those that were harmful to Harry in the past. He could become a more well - rounded character, showing both his old prickly side when dealing with others at Hogwarts, but also a soft, caring side when it comes to Harry.
In this fan fiction, Harry's development is likely to be quite different from the original series. He may start to question the black - and - white view of good and evil he had before. With Snape's intervention in his life, he might see the complexity of people more clearly. At Bloor's, he'll be exposed to a diverse range of characters and situations. This will force him to grow up faster and become more adaptable. He may also develop a more in - depth understanding of magic as Bloor's might have different magical traditions than Hogwarts, and he'll have to learn and adapt to them.
They're popular because it's an interesting 'what - if' scenario. Snape and Harry have a very complex relationship in the original books. So, seeing Snape take on the role of Harry's father flips their relationship on its head and allows for a lot of character development and new storylines.
One popular 'Snape adopts Harry' fan fiction is 'A Father's Love'. It delves deep into how Snape, despite his initial reluctance, gradually grows to care for Harry like his own son. Another is 'Snape's New Family' which shows how Snape's adoption of Harry changes the dynamics within Hogwarts, with teachers and students alike reacting to this new situation.
Another one is 'The Adoption of Harry by Snape'. It's a heartwarming story where Snape overcomes his prejudices. It focuses on how Snape's cold exterior melts as he gets to know Harry better. The author does a great job of showing how their relationship changes over time, from suspicion to mutual respect and finally a deep, familial love.