Well, aside from the main heroes Ladybug and Chat Noir, Alya and Nino are often included. Alya is Marinette's best friend, and she has that curious and adventurous side which can be used in interesting plotlines. Nino is Chat Noir's friend, and his laid - back attitude can be a contrast to the more intense superhero action. Queen Bee is also a popular character to include. Her strong - willed and sometimes bratty personality can create great conflict and character development in fanfiction.
Ladybug and Chat Noir are obviously the most popular. They are the main heroes, and their dynamic relationship is always interesting to explore in fanfiction. Marinette and Adrien, their civilian identities, are also great to include as it adds a layer of complexity with their double lives. Tikki and Plagg, the Kwamis, are also quite popular. Their cute and sometimes mischievous personalities can add a lot of humor to the story.
Marinette's friends like Alya are also popular. In a child fanfiction, Alya could be the one who encourages the child protagonist to believe in the Miraculous heroes. She could share her knowledge of the Ladyblog and help the child get closer to the action. Also, Nino could be involved, maybe he creates a new type of music that has an effect on the akumas.
Ladybug and Cat Noir themselves are obviously very popular. Marinette (Ladybug) and Adrien (Cat Noir) have complex personalities and their relationship is full of potential for fanfiction. Tikki and Plagg, their Kwamis, are also great to include. They can add humor and also provide important insights into the Miraculous lore. Then there's Alya, Marinette's best friend. She can be a great supporting character, either helping Ladybug or getting into some comical misunderstandings.
Ladybug and Cat Noir themselves are very popular. Writers often like to explore their relationship further, whether it's developing their romantic feelings or their friendship as superheroes. Marinette and Adrien, their civilian identities, are also commonly included. Fans enjoy writing about their everyday lives and how they balance that with their superhero duties.
Marinette and Adrien are obvious choices. Their relationship, both as normal students and as superheroes, provides a lot of material for fanfiction. Their crushes on each other, and the comical misunderstandings that often occur, can be explored in a school setting.
Hawk Moth is another character that shows up a lot in fanfiction. Writers like to explore his motives more deeply, or come up with scenarios where he has a change of heart or forms an unexpected alliance. His complex character makes him an interesting subject for fanfiction writers to play around with.
Aside from Ladybug and Chat Noir, Hawk Moth is quite popular in fanfiction. He is the main villain, and many fanfiction writers like to explore his backstory and motives further. There are also some side characters like Alya, Marinette's best friend, who is popular as she often gets involved in the superhero adventures in an indirect way. And of course, Adrien, who is Chat Noir, is a fan favorite due to his charming personality both as a superhero and as a civilian.
Marinette is also very popular. Fanfiction often delves into her life as a normal girl, her struggles with school, her crushes, and how she balances being Marinette with being Ladybug. Her clumsy but endearing personality gives a lot of room for interesting storylines.
Definitely Superman if it's a DC crossover. His super strength and ability to fly could add a whole new dynamic to the battles against Hawk Moth. He could also be a mentor figure to Ladybug and Chat Noir, teaching them about using their powers more responsibly on a global scale.
Definitely Tikki and Plagg. These Kwamis are essential to the Miraculous universe. Their interactions with Cat Noir and Ladybug, as well as their own little quirks and personalities, can make for really fun fanfiction. Additionally, Sabrina, Chloe's sidekick, can be an interesting character to include. She could have her own story of breaking free from Chloe's control or getting involved in the hero - villain drama in some unexpected way.
Ladybug and Chat Noir are obviously very popular. They are the main characters in the original series, and in fanfiction, people love to explore their relationship further. Writers often create scenarios where they grow closer or face bigger challenges together.