Another possible storyline is that they become friends after an accident. Maybe during a Quidditch match, there's a terrible accident and they have to rely on each other to survive. This shared experience makes them see each other in a new light and they start to build a friendship. They then help each other deal with their respective family issues. Draco can give Harry insights into the pure - blood families' ways, and Harry can show Draco a different way of looking at the world, not just through the pure - blood ideology.
A great plotline is when they bond over their difficult family situations. Harry has his issues with the Dursleys and Draco has the pressure from his pure - blood supremacist family. They could find common ground in their struggles against the expectations placed on them. This might lead them to support each other in ways that surprise their classmates and teachers alike, like Draco standing up for Harry against Snape's unfair treatment, or Harry helping Draco break free from his family's dark influence.
One interesting 'Harry Potter and Draco friends' fanfiction could be where they team up to solve a mystery in Hogwarts that the teachers are oblivious to. They use their combined knowledge of magic, Harry's Gryffindor courage and Draco's Slytherin cunning.
One interesting plotline could be them teaming up to solve a mystery within Hogwarts that neither the Gryffindors nor the Slytherins are aware of on their own. For example, a hidden chamber that has secrets about the founders that could change the way the houses interact.
One characteristic is the exploration of character growth. Both Harry and Draco have to overcome their pre - existing prejudices. For example, Harry has to see past Draco's pure - blood supremacist family background, and Draco has to accept Harry as more than just 'the Boy Who Lived'.
In such fanfiction, their friendship could change the dynamics of the entire Hogwarts experience. They might team up for adventures or help each other grow in unexpected ways.
One plot idea could be that they are forced to work together on a school project that requires them to explore each other's family histories. This makes them realize they have more in common than they thought. Another could be that they discover a secret magical realm only they can access together, and in the process, they form a bond. Or perhaps they are both framed for a crime and have to rely on each other to clear their names.
One possible storyline could be that Draco is put under a spell that makes him revert to a baby - like state and needs to wear diapers. This could lead to humorous situations as his Slytherin pride clashes with his newfound helplessness. Another could be a time - travel plot where Draco has to take care of his younger self who is in diapers, and he learns about himself in the process.
A great storyline could be the daughter having a unique magical ability that neither of her parents have. This could lead to her being both feared and admired at Hogwarts. In some fanfictions, she uses this ability to solve mysteries around the school. There could also be a story where she has to choose between following the Slytherin or Gryffindor values more closely, as she has a connection to both through her parents. This internal struggle can make for a very engaging read. And of course, a plot where she gets involved in a time - travel adventure related to her parents' Hogwarts years would be really exciting.
One great example is 'The Unlikely Bond'. In this fanfiction, Draco and Harry are forced to work together on a project for Hogwarts. At first, they're full of mistrust and old grudges. But as they dig deeper into the task, they start to see each other in a new light. Another one is 'A New Beginning'. Here, after the war, they both realize that the wizarding world needs unity, so they decide to set aside their differences and become friends. It shows their journey of understanding and acceptance of each other.
There could also be a fanfiction where Percy has to face his inner demons in a more psychological way. Maybe he's haunted by the memories of all the battles he's fought and the friends he's lost. His friends then have to help him through this tough time, and in the process, they learn more about each other's deeper fears and insecurities.