Yes, there are likely some out there. Fans often create crossover fanfics that combine different universes like 'Hitman' and 'Harry Potter'. These can be really interesting as they blend the magic and mystery of 'Harry Potter' with the stealth and assassin - like nature of 'Hitman'.
A third idea is to create a crossover where the villains from both worlds team up. The evil forces in the Sorcerer's Apprentice world and Voldemort's Death Eaters could join forces. The heroes from both universes would then have to work together to defeat this combined evil. This would involve the Sorcerer's Apprentice character and Harry Potter, along with their friends, strategizing and using their unique magical abilities.
A very common one is Sherlock Holmes. Imagine Harry being raised by the brilliant detective. He would grow up with a sharp mind for deduction, which could be very useful in solving the mysteries within the wizarding world. Another is Gandalf from 'The Lord of the Rings'. Gandalf could teach Harry a different kind of magic and wisdom, which would shape Harry into a very different kind of wizard.
Severus Snape is also a popular choice. His complex character and vast knowledge of magic can create interesting dynamics when he meets characters from different magical worlds. He could either be a mentor or an antagonist in these crossovers.
Edward Cullen and Harry Potter are often popular. The contrast between Edward's vampire nature and Harry's wizardry makes for an interesting dynamic. Fans like to imagine how they would react to each other's powers and the situations they face.
I think Michael Corvin could be an interesting crossover character. He's a hybrid in the Underworld series, which means he has a unique set of abilities. In the Harry Potter world, he could be seen as a strange new kind of magical being. He might be able to help the wizards understand different types of magic that are more physical and instinct - based like his own. Also, his journey of self - discovery in the Underworld could be paralleled in the wizarding world as he tries to find his place among the wizards and witches.
He could interact with characters from the crossover world who are used to the concept of motherhood. For example, if it's a crossover with a fairytale world, he might interact with fairy godmothers who could offer him advice on how to be a good mother.
One possible fanfiction could be about how Rumplestiltskin, with his dark magic, crosses paths with Belle, his love interest. Emrys, who is Merlin in some lore, might be a guide or a powerful figure who tries to balance things. And Harry, coming from the wizarding world, could be brought into their realm by some magical accident. He might initially be confused but then use his skills to help or cause chaos, depending on the plot.
One idea could be that Megara, with her sharp wit and street - smart nature, finds herself in the wizarding world of Harry Potter. She could team up with Harry and his friends, using her own unique skills to help them out in a dangerous situation, like facing a new dark wizard threat.
One idea could be that Tinkerbell finds her way into the wizarding world of Harry Potter. Maybe she gets accidentally transported there by some magical mishap. She could use her fairy magic in Hogwarts, like helping to repair broken objects in a more sparkly and unique way compared to the Reparo charm.