Sure, it's quite possible. Fanfiction writers love to blend different fictional worlds. In a 'The Mummy (2017)' and 'Harry Potter' crossover, we could see the mummy's powers being pitted against the spells of Hogwarts students. Maybe the mummy is brought back to life in the wizarding world and causes chaos. There are endless possibilities for interesting storylines in such a crossover fanfiction.
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.
A popular one is 'Fem Harry and the World of Middle - earth'. This fanfic is really interesting because it crosses over the Harry Potter universe with Tolkien's Middle - earth. Here, Fem Harry has to adapt to the very different cultures and magic systems in Middle - earth, and there are some great character interactions that add depth to the story.
Yes, it could be. It's a very interesting and unique concept. Combining Harry Potter with the Riddler from Batman is quite unexpected. It might involve putting Harry Potter in a situation where he has to solve riddles like the Riddler creates, or perhaps there are elements of mystery from the Riddler's world incorporated into the magical world of Harry Potter.
One idea could be that the Avengers are somehow transported to the wizarding world. They might be initially confused by the magic but then start to work with the Hogwarts students and teachers to fight a common enemy, like a dark wizard who has also harnessed some sort of Muggle - like technology to become even more powerful. For example, Voldemort could team up with Hydra remnants to create a super - weapon that threatens both the magical and non - magical worlds.
A fun concept could be a Transylvanian wizard coming to Hogwarts as an exchange student. This wizard has a pet dragon that is different from the ones in the UK. He brings with him knowledge of Transylvanian magic, like how to use the power of the full moon in a different way than British wizards do, which intrigues Harry and his friends.
One idea could be that the characters from Riverdale somehow find themselves in the wizarding world of Harry Potter. Maybe Jughead could be a Muggle - born wizard who discovers his powers while at Hogwarts. He might write about his strange new experiences in his journal, just like he does in Riverdale.
One idea could be that Loki, being the mischievous character he is, finds his way into the wizarding world of Harry Potter. He could start causing chaos in Hogwarts, perhaps by disguising himself as a student or a professor and playing pranks that are far more elaborate than those of the Weasley twins. For example, he might turn the entire Great Hall into an ice rink during breakfast time.
One idea could be that the Hulk somehow gets transported to the wizarding world. Maybe a magical experiment gone wrong by a Hogwarts student creates a portal. The Hulk's brute strength would be a shock to the wizards and witches. He could end up causing chaos in Hogwarts, knocking down walls and scaring students. Wizards would try to use spells on him, but his strength might make him resistant at first.
Another possibility is a scenario where Voldemort decides to expand his reach into the non - magical world and Batman becomes aware of this threat. He would then enter Hogwarts undercover to learn about magic and form an alliance with the Order of the Phoenix. The contrast between Batman's brooding, non - magical detective nature and the magical world would make for an interesting story.