A common plotline in these fanfictions is that Draco and Harry are in a relationship and decide to adopt. They might adopt a child who is being bullied at Hogwarts for being different. As they raise the child, they also have to deal with their own past traumas and how it affects their parenting. For example, Draco's past with the Death Eaters and Harry's experiences with Voldemort. They use their love for the child and each other to overcome these obstacles and build a loving family.
In some fanfictions, the plotline could be that Draco and Harry adopt a child who is in danger from a dark wizard. They then have to go on the run, protecting the child and each other. It's a story of adventure and family. Also, there could be a story where they adopt a child who has a connection to an ancient magic, and they must figure out how to help the child control it while also dealing with their own relationship. Or perhaps they adopt a child who is a werewolf cub, and they face the stigma within the wizarding community while trying to raise the child with love.
One common plotline could be Draco's struggle to fit into his new family. He might have a hard time adjusting to their values and ways of life, which could lead to internal conflicts. For example, if his adopted family is very Muggle - loving and he has been raised with pure - blood supremacist ideas. Another plotline could be Draco's discovery of a new magic or magical ability because of his new family's influence. Maybe they have a unique magical heritage that he starts to tap into.
A common plotline is how their friendship or rather new - found brotherhood affects the Hogwarts houses. Since Draco is a Slytherin and Harry a Gryffindor, their bond could start to break down the long - standing rivalries between the houses. They might work together to create a more united Hogwarts. Additionally, their relationship could change how they view the wizarding war. Instead of being on opposing sides as they initially were in the original story, as siblings they might try to find a more peaceful solution to the conflict.
One interesting plotline could be them working together to solve a mystery within Hogwarts that the regular faculty can't handle. They combine their unique skills - Harry's courage and leadership, Hermione's intelligence and Draco's knowledge of the Slytherin side of things. For example, they might be on a quest to find a hidden magical artifact that has been causing strange occurrences in the school. This forces them to put aside their differences and really function as a pack.
One common plotline is the internal struggle Draco faces. He has been brought up in a family with certain beliefs that are against Harry, but his crush makes him question everything. For example, in some fanfictions, he might secretly protect Harry during a dangerous event at Hogwarts. Another plotline could be the slow - burn relationship. They start off as rivals but gradually Draco's feelings change and he tries to get closer to Harry in small, furtive ways like leaving anonymous helpful notes for him.
One interesting plotline could be Harry growing up in a completely different magical family and having to adjust to their unique traditions. For example, if he was adopted by a family of potion - makers, he'd have to learn their special techniques.
One interesting plotline could be Harry learning about the Black family's dark secrets while being adopted by them. He might discover hidden magic or family grudges that shape his new life.
One possible plotline could be Harry growing up in the Castle family and learning their unique traditions. Maybe he discovers a hidden talent or power that was dormant before. Another could be him forming new friendships within the Castle family's social circle.
One interesting plotline could be Harry's struggle to adapt to the Malfoy family's pure - blood values while still holding onto his own sense of self. Another might be how he forms unexpected friendships within the Slytherin house. And there could also be a plotline about how his relationship with Draco Malfoy changes from enmity to a more brotherly bond.
In some fanfictions, it might be a situation where they are forced to work together in a bathroom renovation project at Hogwarts. They enter the shower area to check on the new magical plumbing. There, they discover a hidden magical artifact. This discovery makes them realize they need to rely on each other's skills, Hermione's book knowledge and Draco's knowledge of dark artifacts. As they search for more information about the artifact in the shower area, their relationship begins to change.
One interesting plotline could be how they deal with their different house loyalties. Ginny is a Gryffindor and Draco is a Slytherin. Their relationship might be a secret at first, and they have to hide it from their friends and families who have strong prejudices against the other house. For example, Ginny might struggle with telling Harry and Ron about her new relationship, as they have had many conflicts with Draco in the past.