One interesting Detective Conan OC fanfic could be 'The New Detective in Beika'. It introduces a new original character who has unique deductive skills and gets involved in Conan's cases. Another great one is 'OC's Adventure in the Black Organization'. It gives a different perspective as the OC tries to infiltrate the Black Organization. And 'OC and Conan's Team - up' is also good, showing how an OC and Conan work together to solve mysteries.
Well, 'The Mysterious OC in Detective Conan World' is a fanfic worth checking out. In this story, the OC has a special backstory that ties into the existing plot of Detective Conan in an unexpected way. There's also 'OC's Encounter with Shinichi'. This one explores what would happen when the OC meets Shinichi before he becomes Conan. Then there's 'OC and the Case of the Vanishing Artifact', which is full of suspense as the OC helps Conan solve a case related to a valuable and missing artifact.
One idea could be creating an OC who is a master of disguise, like Conan, but with a unique backstory. Maybe they are from a different country and have their own reasons for getting involved in the detective work in Japan. Another idea is an OC that has a special gadget - something that hasn't been seen in the original series yet, like a device that can analyze poisons instantly. And a third idea could be an OC who is a childhood friend of Shinichi's that has some hidden talents related to solving mysteries that come to light after his transformation into Conan.
Well, you could have an OC that is a childhood friend of Shinichi who has a photographic memory. This OC could recall small details from their past that end up being crucial in solving current cases. Or perhaps an OC who is an expert in a very specific field, like ancient languages, and Conan has to rely on this OC's knowledge when a case involves old inscriptions or manuscripts. Also, an OC who has a connection to the Black Organization, either as a former member trying to reform or someone unknowingly involved in their plans, could add a lot of drama to the fanfiction.
One interesting OC concept could be a detective with a special ability like super hearing. They might be able to pick up on small sounds that help in solving cases, much like Conan's sharp observational skills but in a different way.
One interesting SVTFOE OC fanfic could be 'The Star-Crossed Adventure of My OC'. It has a great plot where the original character embarks on a journey through different dimensions in the SVTFOE universe. Another is 'OC's Secret Powers', which delves into a unique power that an OC has and how it changes the dynamics in the story.
One great Detective Conan x Ran fanfiction is 'A New Adventure for Conan and Ran'. It shows a different side of their relationship during a mystery in an old castle. Another one could be 'Ran's Discovery' which delves into how Ran might find out Conan's true identity in a really unique way. There's also 'Conan and Ran: A Future Together' that speculates on their future relationship after Conan reveals his identity.
One interesting Conan Edogawa fanfic could be about his adventures in a parallel universe where he doesn't have to hide his true identity as Shinichi. In this fanfic, he can freely use his intelligence to solve crimes without the guise of a child. Another could be a story where he teams up with characters from other detective shows to solve a huge mystery that spans across different fictional worlds. And there might be a fanfic focusing on his relationships with the other kids in the Detective Boys, exploring their deeper bonds and how they support each other in more complex ways than shown in the original series.
There's also 'OC Adventures in Gravity Falls'. In this fanfic, the original character teams up with Dipper and Mabel to solve a new mystery that has emerged in the town. It does a great job of integrating the OC into the existing group dynamic, and the plot is full of twists and turns that keep you hooked.
One great 'Mortal Instruments' OC fanfic is 'The Lost Shadowhunter'. It has a really engaging plot with a well - developed original character who gets involved in the complex world of Shadowhunters in a unique way.
One interesting Detective Conan kidnapped fanfiction could be where Conan is kidnapped by a new, mysterious criminal organization. In this story, the kidnappers might be after his knowledge of the Black Organization. They could try to force him to reveal secrets, and Conan has to use his wits to escape while still in his shrunken form.
Some Detective Conan fanfiction novels are about time - travel scenarios. Imagine Conan going back in time to prevent the initial incident that led to him being shrunk. It's a really cool concept. Also, there are fanfictions where the Black Organization has different motives and more complex hierarchies. This can add a whole new layer of mystery and intrigue to the story. Oh, and fanfictions that feature crossovers with other detective or mystery series can be really interesting too.