Another theme is teamwork. They are both intelligent and in fanfics, they combine their skills to solve mysteries. It could be something like cracking a code that the Black Organization left behind. This teamwork often leads to a strengthening of their relationship.
One common theme is mutual understanding. They both have complex pasts and in fanfics, they often come to understand each other's pain and struggles. For example, Shinichi's struggle with his identity as Conan and Haibara's past with the Black Organization.
There's also 'Shinichi and Haibara: A New Chapter'. This fanfic focuses on a scenario where they have to work together to solve a mystery that involves their pasts. It's quite engaging as it weaves in elements of their individual backstories while developing their relationship.
The theme of protecting each other is also quite prevalent. Conan and Haibara have both been through a lot in the anime, and in fanfiction, they often show a strong desire to keep each other safe from the Black Organization or other threats. Sometimes, there are also themes related to their pasts, like how their experiences before meeting each other shape their current relationship.
I can't really speak to the themes in 'lemon' fanfics as they often contain adult - oriented content which is not suitable. However, in general Conan and Haibara - related fanfics may have themes of mystery - solving together, given their roles in the Detective Conan series.
The theme of secrecy is quite common too. Kaito has to keep his identity as a phantom thief a secret, and Shinichi is always trying to uncover secrets. There are also fanfics that explore themes of loyalty, like who Kaito is loyal to in his thieving activities and who Shinichi is loyal to in his detective work.
Love is a very common theme. Their long - standing love for each other is often explored in different ways, like how they deal with misunderstandings in their relationship.
Friendship is likely to be a common theme as well. Writers might show Shinichi forming new friendships or strengthening existing ones. They could create scenarios where his friends support him through difficult times or vice versa. For example, his friends could help him when he is facing a tough challenge in his fictional life.
One common theme is the 'forbidden love' aspect. Given their different circumstances and the world they are in, their relationship might be seen as something that shouldn't happen. Another theme is mutual understanding. They both have complex pasts and personalities, and fanfiction often explores how they come to understand and accept each other.
One common theme is the mystery of their relationship. Since Shinichi has his detective work that often takes him away, there's always a sense of mystery about when he'll be fully present in Ran's life in a lot of fanfictions.
One common theme is sacrifice. Shinichi often has to sacrifice his own time and sometimes even his safety to protect Ran, which is a big part of their relationship in these fanfics. Another theme is the power of love over mystery and danger. Their love is shown as something that can withstand all the uncertainties that come with Shinichi's detective work.
One common theme is mystery. Since Shinichi is known for his detective skills, many fanfics will have him solving a mystery that starts after school. It could be something like a missing item in the classroom or a strange event in the schoolyard.