One plot idea could be Tsukune and Ria going on a journey together to discover a hidden power within the Rosario Vampire world. This could involve them facing various monsters and challenges along the way, and their relationship growing stronger as they rely on each other.
A more romantic plot could involve Yukari developing deeper feelings for Tsukune and trying to confess her love in a world full of supernatural distractions and challenges. It could show how their relationship might develop in a different way from the original story.
One plot idea could be Tsukune's further exploration of his unique powers in the Rosario Vampire world. He might encounter a new type of enemy that challenges his abilities in ways he hasn't faced before. Another could be a love triangle involving Tsukune, Moka, and another character, creating a lot of drama and tension. Maybe Tsukune has to go on a quest to find a lost artifact that has significance in the vampire world, and along the way he discovers more about his own heritage.
Some fanfictions focus on what - if scenarios. What if Tsukune was actually a powerful vampire from the start? How would that change his relationship with Mizore? There are also fanfictions that deal with challenges to their relationship, like a rival for Tsukune's affections who is also a powerful monster. This creates a lot of drama and tension in the story as Mizore has to fight for Tsukune's love.
Fanfiction could also center around Mizore and Tsukune training together. Since they both have different powers, they could learn from each other. Tsukune could teach Mizore about human resilience and determination, while Mizore could show Tsukune how to better control his powers, especially when it comes to the more vampiric aspects. Their training sessions could be filled with both comical and intense moments.
One idea could be Tsukune learning a new and powerful vampire ability. For example, he discovers he can manipulate shadows in a way unique to him, which helps him in battles against other supernatural foes in the Rosario Vampire world.
Well, a simple plot could be that Female Tsukune is new to the school and accidentally catches the eyes of several interesting characters, thus forming a harem. They each try to court her in their own unique ways. A vampire might use his charm and knowledge of the night to impress her, a witch could use magic to create beautiful things for her. As the story progresses, Tsukune has to figure out who she really likes among them while also dealing with the jealousy and drama that comes with a harem situation.
One interesting plot idea could be Tsukune having to protect his harem members from a new powerful vampire threat that has emerged in the school. This would involve a lot of action scenes where Tsukune uses his growing powers.
One interesting plot could be Tsukune and Ruby going on a secret mission within the Yokai Academy. They might have to face a new type of supernatural threat that neither of them has encountered before. This would test their skills and their relationship as they rely on each other to survive.
Another option is to check out some dedicated anime fanfiction forums. There might be threads specifically for Rosario Vampire fanfictions that feature Tsukune and Ria. Sometimes, these forums have a more curated collection as the users are often more into the specific anime.
Another fanfiction could be about Nekonome getting into trouble and Tsukune coming to her rescue. For example, Nekonome could accidentally break a precious magical item in the school and Tsukune uses his newfound powers to fix it before anyone notices. This would show their loyalty and friendship towards each other.