There are some really cool plot ideas in this type of fanfiction. One could be a story where Harry Potter is actually related to an Asgardian. Maybe his mother was an Asgardian in hiding. This would completely change his backstory and how he relates to the wizarding world and his powers. Or perhaps Voldemort has an interest in Asgardian magic and tries to use it for his own evil purposes, leading to a whole new set of challenges for Harry and his friends.
One interesting plot idea is when the magic systems of Asgard and Hogwarts collide. For example, the use of seiðr (Asgardian magic) in the wizarding world of Harry Potter. Another is characters from Asgard attending Hogwarts. Imagine Loki causing chaos in the halls of Hogwarts or Thor trying to fit in with the wizards.
One possible plot is that Voldemort somehow has a connection to an Asgardian villain. Harry, being the hero, travels to Asgard to find a way to defeat Voldemort once and for all. Along the way, he meets the Asgardian gods. They initially doubt him but soon realize his strength. Harry then combines his wizardry with Asgardian magic to face the dual threats of Voldemort and the Asgardian foe.
A really cool plot is when the Wakandan warriors are brought into the wizarding world to fight against the dark forces. Their combat skills combined with magic could make for some epic battle scenes. Also, there could be a story where a magical artifact from Harry Potter ends up in Wakanda and causes a stir, leading to a journey of discovery about both worlds. This would involve characters from both universes working together to understand the significance of the artifact and how it affects their respective worlds.
One interesting plot idea is Doflamingo using his string powers to manipulate the wizarding politics. He could be like a puppet master, pulling the strings of important wizarding figures. Another is a team - up between Doflamingo and some of the darker characters in Harry Potter, like the werewolves or certain Death Eaters, to create a new regime in the wizarding world.
Another idea is that the magic in the Harry Potter world somehow combines with Wonder Woman's powers. So, Harry might be able to use his magic in a new way after being influenced by Wonder Woman's strength and abilities. This could lead to a whole new way of fighting against Voldemort or other dark forces.
One interesting plot idea is having the characters from Fast and Furious enter the Triwizard Tournament in the Harry Potter world. Imagine Dom Toretto competing in a magical challenge on a broomstick. Another is Harry Potter characters using magic to help the Fast and Furious gang in a high - stakes car chase against some dark magic - using villains.
A really interesting plot idea is the concept of a magical - Force hybrid power. In some fanfictions, characters like Harry Potter and Anakin Skywalker discover that their powers can be combined in unique ways. For example, using the Force to enhance spell - casting range or using magic to heal wounds that the Force couldn't fully heal on its own.
One interesting plot idea is a time - travel scenario. Damon could be sent back in time to the era of the founders of Hogwarts. He might have to adapt to the magic system there while also dealing with his vampire nature. Another idea is a magical experiment gone wrong that somehow links Damon's world to the Harry Potter world and they have to figure out how to separate them again.
One interesting plot idea could be Snart using his cold - gun in the magical world of Harry Potter. Maybe he has to face off against a dark wizard and his cold - based technology gives him an unexpected advantage. Another could be a story where Snart is accidentally transported to Hogwarts and has to find a way back home while dealing with the magical chaos around him.
A really interesting plot could be a magical duel between a powerful wizard from Harry Potter's world and a magic - using pony in Equestria. It would be exciting to see how their different types of magic clash and interact.
Another great plot idea is the cultural exchange between the two universes. The proper British wizarding society in Harry Potter and the more gothic, dark world of Diabolik Lovers. How would the characters from each world react to the different social norms? For instance, how would the vampires react to the Hogwarts house system? And how would the wizards deal with the vampires' feeding habits? This can lead to a lot of humorous and also thought - provoking situations in the fanfiction. It can also explore themes like acceptance and prejudice as the two groups interact.