The plot might involve Harry trying to figure out how he got pregnant in the first place if it's in a world where male pregnancy is not the norm. He could be alone because he doesn't want to burden his friends or family. Harry would then have to learn about pregnancy on his own, from reading books or searching the internet. He might also face financial difficulties as he prepares for the baby's arrival, but through his own determination and some unexpected help, he starts to build a new life for himself and the baby.
Perhaps Sakura is alone as a result of a broken relationship. She finds out she's pregnant and has to make a decision about whether to keep the baby or not. If she decides to keep it, she starts to build a new life for herself and the unborn child. She might learn new skills, make new friends who support her during the pregnancy, and gradually become more confident in her ability to be a single mother.
The story could be that Harry grows up alone in the Muggle world, completely unaware of his wizarding heritage until much later. He might face bullying and isolation in the Muggle school. When he discovers his true identity, he has to quickly adapt to the wizarding world all by himself. This could lead to him making some hasty and unwise decisions as he has no one to guide him.
One possible plot could be that Harry and Ginny are overjoyed at the news of Ginny's pregnancy. They start preparing for the baby's arrival by setting up a nursery in their home at Grimmauld Place. Ginny might take a break from Quidditch, and Harry would be extra protective, constantly worrying about her safety. Their friends like Hermione and Ron would be excited and offer their help, bringing baby clothes and giving advice based on what they've read in wizarding parenting books.
Hermione could be one of the characters to help Harry. She's intelligent and resourceful, so she could provide practical help like finding a good doctor or helping with magic - related pregnancy issues if it's in a magical world. Another could be Hagrid. He has a big heart and could offer emotional support and perhaps a place for Harry to stay if he needs it.
In a 'Harry Fights Alone' fanfiction, the plot could involve Harry being betrayed by his friends. Maybe they are put under a spell that makes them turn against him. Harry then has to face the dark forces all by himself. He might have to rely on his own wits and the few spells he has mastered alone. For example, he could be in a situation where he has to battle Voldemort's minions without Ron and Hermione to back him up, and he discovers new powers within himself during this struggle.
In this kind of fanfiction, one possible plot could be that Naruto loses all his friends due to some unforeseen and tragic events. Maybe he makes a great sacrifice to save the village, but in the process, he becomes estranged from everyone. His friends might misunderstand his actions, or he could be cursed in a way that drives people away. Eventually, he dies alone, with his heroic deeds forgotten by most.
One possible plot could be that Harry and Kara are in a relationship. When Kara discovers she's pregnant, they face challenges together. Maybe they have to deal with the reactions of their friends and family, and they struggle to balance their own dreams and the upcoming arrival of the baby. For example, Harry might be on the verge of a big career opportunity, but he has to put it on hold to support Kara during her pregnancy.
In this fanfiction, Harry could be alone because he feels estranged from his friends who have moved on with their lives in different ways. So he takes on a solitary mission to protect the wizarding world in the shadows. He becomes a sort of unseen guardian, constantly thwarting small threats that could potentially grow into big problems, all while dealing with his own loneliness and the memories of the war.
Well, one possibility is that Percy has to learn to fend for himself in a harsh world. Maybe he discovers unique powers within himself as he faces various challenges alone. For example, he could learn to hunt and build shelters all by himself, much like a survival story.
Well, perhaps in this fanfiction, Ash is on a solo quest in Sinnoh to find a way to improve his Pokémon training skills even further. He could be traveling from one town to another, meeting new trainers who give him unique tips. Along the way, he might encounter some legendary Pokémon that test his abilities in unexpected ways. This would not only be a great adventure for Ash but also a chance for him to grow as a trainer without the help of his friends.