A 'ben 10 eon fanfic' could focus on Eon's powers. For example, a story where Eon loses his powers temporarily and has to rely on his wits and the help of some unexpected allies. This could show a different side of him, perhaps a more vulnerable side. Or it could be about Eon creating his own army of alternate versions of Ben's aliens, and Ben has to find a way to counter this unique threat.
You could write a fanfic where Eon travels to a parallel universe where Ben doesn't exist. In this universe, Eon has the chance to rewrite history and become a hero. But as he starts to make changes, he realizes that the balance of the multiverse is at stake. He then has to decide whether to continue his self - serving ways or try to fix what he's broken.
One idea could be exploring Ben's new abilities as Ben 110 when dealing with the Highbreed. Maybe he discovers a unique power that can temporarily transform Highbreed into a more peaceful form. Another could be a story where Ben 110 has to team up with a group of Highbreed rebels against the tyrannical Highbreed leaders. It could also involve Ben 110 traveling to the Highbreed homeworld and learning about their culture and how to better co - exist with them.
One interesting idea could be exploring an alternate universe where Ben's Omnitrix has different aliens with unique powers. For example, aliens that can manipulate time in ways not seen in the original series. Another idea is to focus on a story where Ben has to team up with his enemies to face a greater threat. This would create a lot of interesting character dynamics.
A really interesting plot could involve a time - traveling aspect. Ben and Julie accidentally travel back in time to when Ben first got the Omnitrix. They have to be careful not to disrupt the timeline while also trying to find a way back to their own time. Along the way, they could meet younger versions of characters they know and have some really fun and emotional interactions. This could also lead to Ben learning some important lessons about his powers from his past self.
One idea could be exploring a new alien form that wasn't in the original series. Maybe an alien with the power to control time in a unique way. Another idea is to have Ben go on a mission in a completely different galaxy, facing new challenges and enemies.
One idea could be a story where Ben and Gwen have to team up to face a new alien threat that is immune to Ben's usual alien forms. Another could be a fanfic set in an alternate universe where Ben and Gwen have swapped their abilities. Maybe a story about their adventures during a time - traveling incident.
Another plot could be that a new villain emerges who has the power to control both human and Myaxx technology. Ben and Myaxx must figure out a way to break this control and stop the villain from taking over the galaxy. They start by gathering intelligence on the villain's lair and formulating a plan that utilizes Ben's shape - shifting abilities and Myaxx's knowledge of her own technology.
One idea could be that as a girl, Ben has to face different social challenges while still using the Omnitrix to save the day. For example, some might underestimate her because of her gender, but she proves them wrong with her heroic deeds.
Another interesting plot could be that some of Ben's alien forms are mistaken for new mutants in the Marvel Universe. He then has to prove that he's not a threat while also helping the X - Men deal with a common enemy that is interested in the genetic makeup of both mutants and Ben's alien forms.
One idea could be that Ben, using his alien forms, has to battle Dracula's minions in a spooky castle. Maybe he teams up with some local vampires who oppose Dracula's tyrannical rule. Another could be that Dracula tries to turn Ben into a vampire to use his alien powers for his own evil deeds.
A plot could involve a group of young Highbreed who are curious about Earth and its cultures, and they secretly befriend Ben. This would lead to a series of adventures where they have to hide their friendship from the more traditional and hostile Highbreed. They could learn a lot from each other, and Ben could teach them about the value of diversity and cooperation.