A plot twist could be that the family that abandoned him isn't his real family at all. In the fanfiction, it could be revealed that he was switched at birth. His real family could be out there looking for him. Or perhaps the family was under a powerful spell when they abandoned him. Later, the spell is broken and they come back to him full of remorse and trying to make up for their actions.
Sometimes, the plot twist is that Harry's abandonment was part of a grand plan. There could be a prophecy that stated he needed to be on his own to grow into a powerful wizard. So, his family's actions were guided by this prophecy. Another possibility is that the family was being blackmailed into abandoning him. Later, Harry finds out about this and has to decide whether to forgive them or not.
One common plot twist is that his family actually has a noble reason for abandoning him. Maybe they were trying to protect him from a greater evil that they knew was coming for him. Another is that Harry discovers he has a hidden power that his family was afraid of, which led to the abandonment. For example, he could have a power that is considered dark but is actually something that can be used for good.
A plot twist might be that Naruto's family abandonment was part of a prophecy. In the fanfiction, it could be that in order for Naruto to fulfill a certain destiny, he had to be abandoned so that he could grow in a specific way. Also, there could be a plot twist where the person Naruto thought was his enemy all along was actually the one who knew the truth about his family and was trying to guide him back to them in a roundabout way.
A plot twist might be that Naruto, after being abandoned by his family, finds a new 'family' in unexpected places. For example, he could bond closely with a group of outcasts in the village who understand his pain. Or perhaps, the family's abandonment was part of a larger conspiracy within the ninja world, and Naruto's journey to uncover the truth behind it becomes a major part of the story.
A plot twist could be that the person who breaks Harry's heart has a secret identity. They could be a spy from an enemy group, but during their time with Harry, they actually fell in love too. However, their loyalty to their original group makes them break Harry's heart. Or perhaps the heartbreak is due to a time - traveling incident. Harry meets someone from the future who has to leave him in order to preserve the timeline. And also, it could be that the one who breaks Harry's heart is actually under a spell that makes them act out of character, and when the spell is broken, they try to come back to Harry but it's too late.
In such a fanfiction, Naruto might grow up feeling extremely lonely and having trust issues. He could become more self - reliant, forging his own path without any family support. Maybe he would be more eager to prove himself to the village, not just to gain their acceptance but also to show his absent family what they missed out on.
One possible plot could be Naruto growing up alone and having to fend for himself. He might develop a very independent and distrustful nature towards others at first. Maybe he starts to question his self - worth, but then through his own determination and some unexpected friendships, he begins to rise above his difficult past and prove himself to the village in ways no one expected.
In many of these fanfictions, a common plot twist is the exploration of Snape's past relationship with Lily in light of this new information. Maybe there were more secret meetings or promises made between them that Harry uncovers. Another plot twist could be that the wizarding world's view of Snape completely changes when the truth is revealed, and Harry has to deal with the new - found fame or notoriety that comes with being Snape's son. Also, there could be a plot twist where Harry discovers that Snape had been training him in subtle ways all along, without Harry realizing it was his father - son connection at play.
One possible scenario could be that Harry grows up on the streets, learning to fend for himself and developing a tough exterior. He might encounter some kind of mentor figure who helps him discover his magical abilities in a very different way than in the original story.
Some fanfictions might have a plot twist where Naruto's family is alive but has lost their memories. So Naruto has to help them regain their memories while also dealing with the fact that they are his family. Another common twist is that his family has been living in another dimension all this time. And when Naruto finds out they're alive, he has to find a way to bring them back to his world. There could also be a twist where his family was actually kidnapped and held captive by an enemy, and Naruto has to rescue them.
One interesting plot twist could be that the letter is delivered by a completely unexpected character, like a house - elf instead of an owl. This would change the whole dynamic of how Harry receives this important news.
Well, it could be that Harry fakes his death and then assumes a completely new identity. He could be living among the very people he was fighting against, gathering information. And the twist is that he starts to have doubts about the side he was on all along, as he gets to know his enemies better from the inside.