Another possible storyline is Gilgamesh having a conflict with an ancient evil that has resurfaced in the Marvel universe. Maybe an old enemy from his own time that has found a way to return. He would then have to use his powers, which could be enhanced versions of his historical feats in the Epic of Gilgamesh, to defeat this enemy and protect the modern world from destruction.
A crossover fanfiction might focus on a quest where characters from all three universes team up. Imagine Naruto, with his determination, Gilgamesh, with his vast knowledge and power, and Fairy Tail wizards, with their unique magics, working together to defeat a common enemy. They could learn from each other's skills and powers, like Naruto learning about different types of magic and Fairy Tail members learning about chakra.
One possible storyline could be a crossover where Naruto and Deathstroke are forced to team up against a common enemy. Maybe a powerful demon or a group of rogue ninjas and mercenaries. Naruto's positive and determined attitude could contrast with Deathstroke's more cynical and self - serving nature, leading to some interesting character interactions.
An OC in The Originals fanfiction might be a human who has a special connection to the supernatural world. For example, an OC could be a historian who discovers secrets about the Originals' past and uses that knowledge to interact with them. This could lead to all sorts of adventures as the OC tries to navigate the dangerous world of vampires, witches, and werewolves while also dealing with the complex personalities of the Mikaelsons.
In some fanfiction, there could be crossovers with other Marvel properties. For instance, the Agents of Shield team could meet the X - Men. This would create a whole new set of dynamics and story possibilities. They might have to work together to stop a mutant - hating villain who is also after SHIELD secrets. Another idea could be a story where they encounter Doctor Strange and have to deal with a magical threat that they are completely unprepared for.
Another possibility is that Leah Clearwater is mistaken for a new type of jinchuriki. Her powerful and somewhat otherworldly abilities might be misconstrued in the Naruto world. This could lead to her being hunted or protected, depending on who discovers her first. And as she tries to clear up the misunderstanding, she gets involved in the complex politics and power struggles of the ninja villages.
In some fanfiction, Trunks could be involved in a time - travel related plot within the Fairy Tail universe. Maybe he discovers a way to travel through time in this new world, and has to prevent a dark future where the guild is destroyed. He would use his knowledge and skills to change the course of events, while also learning about the different magics and cultures in Fairy Tail.
In some fanfictions, Tobi might have a backstory related to Fairy Tail that was previously unknown. For example, he could be a long - lost member's relative. This would add a new layer of mystery and drama to the story. He could then be on a quest to discover his connection to the guild, all while getting involved in the guild's adventures.
One interesting storyline could be an OC who is a Saiyan from a lost colony. They come to Earth seeking answers about their heritage and end up training with the Z - fighters. They might have unique powers that are a blend of traditional Saiyan abilities and something new, like the ability to manipulate energy in a different way than Goku or Vegeta.
One interesting storyline could be a mission where Naruto, Mei and Tsunade have to work together to stop a powerful enemy. Naruto's strength and determination, Mei's unique jutsu and Tsunade's medical and combat skills would combine in exciting ways. For example, Naruto could be on the front lines with his Rasengan, Mei could use her water jutsu to control the battlefield, and Tsunade could heal any injuries and also deliver powerful punches when needed.
One possible storyline could be Delsin teaming up with Team RWBY to fight a new, powerful Grimm. He might use his unique powers, like his smoke or neon abilities, to complement the girls' skills. For example, his mobility could help in quickly getting to different parts of the battlefield.