One interesting plotline could be a different take on Ladybug and Chat Noir's relationship during 'that night'. Maybe they face a new villain together and their bond deepens in a unique way.
In addition to Ladybug and Chat Noir, there might be new characters created specifically for this fanfiction. They could be other Miraculous holders that come out during 'that night' to assist Ladybug and Chat Noir in a big battle. Or perhaps a mysterious character who has some knowledge about the Miraculous that could change the course of the night for our heroes.
One interesting plotline could be how Ladybug and Chat Noir finally reveal their identities to each other in a very unexpected and emotional moment. Maybe it happens during a battle where they are forced to trust each other completely.
One interesting plotline could be an alternate version of how Ladybug and Chat Noir meet. Maybe in this Gaslight version, they meet under more dangerous and mysterious circumstances, like in a fog - covered alley during a crime spree. Another could be a different take on their powers, perhaps with some new abilities or limitations specific to this fanfiction's universe.
One interesting plotline could be a different origin story for the Miraculous. Maybe in this fanfiction, the Miraculous were created not just for good but had a more complex backstory involving an ancient civilization's struggle between light and dark. Another could be a love triangle between Marinette, Adrien, and a new character introduced in the fanfiction. This new character might have their own Miraculous and their presence shakes up the relationship dynamics.
One interesting plotline could be Simon creating more complex and devious challenges in the 'Simon Says' game that the Miraculous heroes have to overcome. For example, he might make rules that directly conflict with their moral code, forcing them to find loopholes to still defeat him without breaking their principles.
One plotline could be a love spell gone wrong. For example, a character accidentally casts a love spell on the wrong person, leading to chaos and confusion as the person starts acting out of character in their 'love' for someone unexpected. This can create humorous and tense situations as the other characters try to reverse the spell.
One common plotline is about Luka helping Marinette deal with her feelings for Adrien. He becomes her confidant and through that process, they start to develop deeper feelings for each other.
One possible plotline could be that Marinette's best friend reveals her secret identity to someone she shouldn't. This would make Marinette feel extremely betrayed as her identity is crucial in the Miraculous world. Another could be that the people she thought were on her side in the fight against Hawk Moth turn against her due to false accusations. For example, if someone spreads the rumor that Marinette is working with Hawk Moth, her allies might start to doubt her and treat her coldly, which is a huge betrayal.
I can't really recommend or go into detail about spanking - related plotlines as they may not be suitable or appropriate for all audiences. However, in general Miraculous Ladybug fanfiction might explore different relationships between the characters, like Ladybug and Cat Noir's partnership, or their individual struggles with their secret identities.
One popular plotline could be how they handle the new responsibilities. For example, Adrien might start to worry about protecting his family more, like keeping their identities even more secret from Hawk Moth. Marinette could be designing new baby clothes with her amazing fashion skills. Another plotline could involve their friends' reactions. Alya might be super excited and offer to be the babysitter all the time, while Nino could be giving Adrien some 'dad - to - be' advice.