There's also 'A Crossover of Worlds'. This fanfiction focuses on the clash of cultures between the two universes. It has interesting plot twists where the Death Eaters get involved with the Vongola famiglia. It's full of action and the author does a great job of making the two different magic systems work together.
Another option is FanFiction.net. Although the search there might not be as refined as on AO3, you can still find some good 'khr crossover harry potter fanfiction' by using specific keywords in the search. Also, check out some of the fanfiction communities on social media platforms like Tumblr or Reddit. People often share links to their favorite stories there.
In Harry Potter, a character can be themselves by following their own moral compass rather than the strict rules of Hogwarts. For example, if they believe that house unity is more important than competition, they can act on that. In KHR, a character can be true to themselves by using their skills in a way that aligns with their personal beliefs. If they think violence is not the answer, they can use their fighting abilities to protect rather than attack.
I've heard of 'Potter and the Hitman's Adventure'. In this fanfic, the author takes elements from both series and creates a new plot. For example, Harry could end up learning some of Reborn's combat techniques while still using his wizardry. It's a really fresh take on cross - over fanfictions.
You can start by looking on popular fanfiction websites such as Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, and you can easily search for Harry Potter KHR crossovers using the search bar. Just type in relevant keywords like 'Harry Potter KHR' and browse through the results.
A common theme could be the exploration of the magic that is unique to the time between dusk and dawn. Since Khr is involved, it might also involve themes of self - discovery as Khr navigates the unfamiliar world of Harry Potter during this special time.
One idea could be to have the characters from Harry Potter world attend the Vongola Academy in the KHR universe. They could learn about the different flames and how to use them while also sharing their magical knowledge. For example, Hermione would be really interested in the scientific aspects of the Dying Will Flames and might try to find a way to combine it with her magic.
Authors need to first understand the core elements of both universes. For Harry Potter, it's the magic, Hogwarts, and the fight against Voldemort. In KHR, it's the Mafia families and the growth of Tsuna. Then, they can start by introducing characters from one universe into the other in a believable way. For instance, if Harry were to enter the KHR world, how would he adapt to the different rules and powers there?
One interesting Harry Potter KHR fanfiction could be one where the magic systems of both worlds are combined. For example, characters from KHR might learn some spells from the Harry Potter universe and vice versa. This creates unique and exciting plotlines as they navigate the differences and similarities of the two magical realms.
One great 'dusk to dawn' Khr Harry Potter fanfiction could be 'The Enchanted Dusk' where Khr goes on an adventure through Hogwarts at dusk and discovers a hidden magic that lasts until dawn. It has a really interesting plot that weaves in elements from both the world of Harry Potter and the unique character of Khr.