In Harry Potter and DC fanfics, odd ideas can range from crossovers where Harry Potter characters end up in the DC universe and vice versa. For example, imagine Harry Potter using magic in Gotham City. Another odd idea could be a character from DC, like Batman, somehow getting access to Hogwarts and trying to figure out the magical world's rules. It adds a whole new layer of creativity and unexpectedness to the stories.
You can start by looking on fanfiction.net. It has a large collection of fan - fics from various fandoms, including 'Harry DC fanfic'. Another good place is Archive of Our Own (AO3). It's known for its wide range of fan - created content, and you're likely to find some interesting 'Harry DC fanfic' there.
One great 'Harry DC fanfic' is 'Harry Potter in the DC Universe'. It has an interesting plot where Harry is suddenly transported into the DC world and has to navigate using his magic skills among the superheroes and villains there. Another one could be 'The Wizard of DC' which focuses on how Harry's magical knowledge helps him solve some of the DC universe's most complex problems.
A really odd idea could be a fusion of the Death Eaters and the Suicide Squad. They are both groups with their own dark agendas. The Death Eaters' magic combined with the Suicide Squad's chaos would make for a very interesting and unexpected story. It could be set in a world where the two universes collide.
One great one is 'The Wizard and the Caped Crusader'. It combines the magic of Harry Potter's world with the superhero action of DC. It has a really interesting plot where Harry somehow ends up in Gotham City and has to team up with Batman to fight a new kind of dark magic that's threatening both worlds. Another is 'Magic in Metropolis' which shows Superman dealing with the sudden appearance of Hogwarts students in his city. They bring chaos at first but then they all work together to face a common enemy. There's also 'Potter and the Justice League' which features Harry joining forces with the entire Justice League to take on Voldemort who has made an alliance with some of DC's villains.
One common theme is the clash and融合 of different powers. Since Harry has magic from the Potter universe and then there are all the superpowers in the DC universe, how they interact and sometimes conflict is often explored.
One way the storylines could blend is through a magical event that transports Harry Potter characters to the DC universe where they meet Martians. Maybe a spell gone wrong by Hermione accidentally opens a portal. The Martians, with their unique abilities like telepathy, could interact with the wizards. For example, J'onn J'onzz could communicate with Dumbledore using his telepathy and they could team up against a common enemy like Voldemort who has somehow made his way into the DC universe as well.
Harry Potter and Superman would have an interesting interaction. Superman's super strength and invulnerability might be a source of wonder for Harry, while Superman could be intrigued by the magic Harry wields. Martians, like J'onn J'onzz, could interact with both. J'onn could use his shape - shifting ability to blend in at Hogwarts and learn about magic, and also team up with Superman to face any threats that cross over from the wizarding world.
You can start by searching on popular fanfiction websites like Fanfiction.net or Archive of Our Own. Use specific keywords such as 'Harry Potter DC crossover' in the search bar. Check the ratings and reviews of the fanfictions that come up. High - rated ones with positive reviews are usually a good bet. Also, join fanfiction forums or groups dedicated to either Harry Potter or DC and ask for recommendations from other fans.
There's also 'Potter's DC Adventure'. In this fanfiction, Harry finds himself in the DC world and gradually forms relationships with different characters. It's a great read if you like to see how the two different fictional universes blend together in the context of a harem story. The author does a good job of maintaining the essence of both the Harry Potter and DC worlds.