One plotline could center around them adopting a child. Given their complex backgrounds, they would face unique challenges in raising a child. They might have to deal with the child being bullied because of their fathers' history. The fanfiction could show how they support each other and the child through these difficult times. Also, they could go on adventures together as a family, exploring parts of the wizarding world that are not well - known. It could be a way for them to bond and create new memories away from the prying eyes of the wizarding society.
One possible plotline could be that they discover they are brothers early on in their Hogwarts years. This would cause a huge stir among the students and teachers. They might initially struggle to accept it, especially given their past animosity. But as they get to know each other better, they start to form a bond and protect each other from the various threats in the wizarding world.
One possible plotline could be that Harry is in a magical world where polyamorous relationships are more accepted. He meets two men who are very different from each other. One might be a brave and adventurous wizard like him, and the other could be a more studious and calm character. They all come together through a series of magical adventures and gradually fall in love with each other.
In this fanfiction, a plotline could involve Harry being magically bound to Draco's mom in some way. As a result, he has to stay close to Draco to protect the bond. This could lead to many comical and tense situations between Harry and Draco as they navigate their new relationship. Another possibility is that Draco's mom has left behind a powerful artifact, and Harry is the only one who can find it. Draco, thinking Harry has ulterior motives, tries to stop him at first but then realizes they need to work together. Also, there could be a plotline where Harry accidentally uses a spell that links his mind to Draco's mom, and he has to figure out how to break the link while dealing with Draco's reactions.
The fanfiction could focus on their domestic life. How do they divide household chores? Harry might be used to a more chaotic and friendly environment at the Burrow, while Draco is used to having house - elves do everything. They would need to find a middle ground. Also, their magical abilities could combine in unique ways. Maybe they create new spells together during their time at home, or they use their combined knowledge to improve the security of their home, which could be important considering Harry's history with dark wizards targeting him.
One possible plotline could be that Harry, through some magical accident or inheritance, comes to own Draco's family manor. Draco is then forced to interact with Harry on Harry's terms to regain his family's pride. Another could be that Harry wins a bet against Draco and the terms of the bet are such that Harry now has ownership over Draco's time, making Draco do tasks for Harry.
In some fanfictions, it could be a case of a powerful curse that forces Harry to act against his will. The curse might be placed on him by a powerful dark wizard who wants to create chaos in the wizarding world. Draco is just an unfortunate victim of this curse as Harry, unable to control himself, kills Draco. This then sets off a chain of events where Harry has to deal with the guilt and the consequences of his actions.
One possible plotline could be that Draco steals Harry's underwear as a prank. He might do it to embarrass Harry in front of their classmates at Hogwarts. Another could be that Draco steals it because he has some strange fascination with Harry and it's a way for him to have something of Harry's. Or perhaps it's part of a dare within the Slytherin group that Draco is a part of.
One possible plotline could be that in a dangerous magical situation, like a dark wizard attack during a Hogwarts event. Draco, despite his previous animosity towards Harry, has a change of heart. Maybe he overhears some information about the attack being part of a larger plot against Harry specifically. So, Draco steps in and uses his family's knowledge of certain spells or magic artifacts to save Harry. Another could be in a potion - making class gone wrong where Harry is about to be seriously injured by a rogue potion effect, and Draco, who is actually quite good at potions, quickly whips up an antidote or counter - spell to save Harry.
One possible plotline could be that Harry betrays Draco in a duel. Maybe there was some sort of misunderstanding or a secret deal that Harry made with someone else that required him to turn on Draco during the duel. For example, if there was a dark wizard threatening Harry's friends and the only way to save them was to sacrifice Draco in the duel by using a forbidden spell against him.
A possible plotline could be that Draco, out of curiosity, starts to research Harry Potter's mother. As he delves deeper, he finds out about her selfless love and her powerful magic. This makes him question his own values and beliefs, leading to a transformation in his character.