One idea could be Silver coming from the future to prevent a new threat in the Sonic X universe that the others are unaware of. He might team up with Sonic and his friends in unexpected ways, like using his psychic powers to help them access hidden areas. For example, he could use his powers to levitate Sonic over a large chasm that the others can't cross.
One idea could be Sonic having to deal with his new vampire abilities while still trying to protect his friends from the usual villains. For example, he might struggle with the urge to drink blood but not want to harm his friends. Another plot could involve Sonic trying to find a cure for his vampirism while on the run from vampire hunters who mistake him for an evil creature.
One idea could be Sonic having to face a new and more powerful dark version of the Black Knight. This would test his skills and force him to find new ways to use his speed.
One interesting idea could be creating an OC that has a unique power related to time manipulation. For example, they can slow down time to gain an advantage in races or battles against Sonic and his friends. Another idea is an OC from a different dimension who comes to Sonic's world with strange technology that no one has seen before. It could lead to interesting interactions as Sonic and his friends try to understand this new arrival.
One idea could be that they have to team up to stop a new powerful villain who is causing chaos across different zones. This villain could be creating some sort of energy disruptions that only their combined powers can counter.
A plot idea could be that an evil scientist has created a device that combines the powers of both Sonic's chaos emeralds and Spider - Man's radioactive spider - bite. This new power source is unstable and threatens to destroy both their universes. Sonic and Spider - Man must work together to stop the device. It's interesting because it forces them to understand each other's powers and find a way to neutralize this new threat.
One interesting story could be where the reader is from a different dimension and Silver has to protect them from the chaos that follows. It's a great way to explore the concept of different worlds colliding.
Well, in naruto x sonic the hedgehog fanfiction, a cool idea is the interaction of their friends and allies. Naruto's friends like Sasuke and Sakura could meet Sonic's friends like Tails and Knuckles. They might have to work together to face a common enemy. Maybe an enemy that combines the threats from both their universes, like a villain who has both the power of chakra - stealing jutsu and the ability to slow down Sonic's speed. And also, the different cultures of the two worlds could lead to some funny and interesting situations.
In some fanfictions, they might explore the differences in their personalities. For example, Classic Sonic's more simplistic and straightforward approach contrasted with Modern Sonic's more complex and sometimes cocky attitude. They could start off not getting along due to these differences but then learn to work together. Maybe there's a story where they are both trapped in a strange dimension and have to rely on each other's skills. Classic Sonic's spin - dash and ability to handle more 2D - like terrains, while Modern Sonic can use his homing attack and boost in the more complex 3D areas of the dimension.
One idea could be that Sonic from Sonic X accidentally travels to the Sonic Boom universe and has to adapt to the different environment and new versions of his friends. Maybe he teams up with Sonic Boom Sonic to defeat a common enemy that has found a way to cross between the two universes.
A possible plot could be that both Silver and Tikal are called by a powerful, mysterious force. They find each other on this journey. Tikal's connection to the Chaos Emeralds and Silver's psychic powers interact in unexpected ways. As they face various challenges together, they grow closer. Silver is initially a bit of a loner, but Tikal's warm nature melts his heart, and they end up falling in love.