In some fanfictions, Percy is sent to a post - apocalyptic version of his world. He has to use his demigod skills to survive in a land full of mutated monsters. This is really exciting as it shows Percy in a completely different light, having to adapt to a world where the normal rules no longer apply. Also, there could be a plot where Percy is sent to a world where he has no powers at first. He has to regain them through a series of trials, which makes for a great character - building story.
One interesting plot could be Percy finding himself in a world where the Greek gods have different forms or powers. For example, Zeus could be a benevolent king instead of the often angry god we know. Percy would have to navigate this new world, figure out how to use his own powers in relation to these changed deities, and perhaps find a way back home. Another plot could involve Percy being sent to a world that is a blend of different mythologies, like Greek and Norse. He'd have to deal with new creatures and gods from both mythologies, which would be a real challenge.
In this type of fanfiction, a possible plot is that Naruto is sent to a dimension where time moves differently. He might age at a much faster rate, and he has to quickly master the ways of this dimension to find a way to reverse the time effect on him. Another cool plot could be that he lands in a dimension that is a mirror image of his own, but with opposite personalities for everyone. So he has to deal with a Sasuke who is overly friendly and a Kakashi who is always serious, which makes for a really strange and challenging adventure.
One interesting plot could be Percy's struggle to survive in Tartarus alone. He might have to face the various monsters there without his usual allies. Another plot could involve him finding a way to escape Tartarus using his wits and the powers he has. Maybe he discovers some secrets about Tartarus that no one else knows.
One interesting plot could be Percy having to deal with new mythological threats while trying to balance his college studies. For example, a group of rogue satyrs causing chaos on campus. Another plot might involve Percy and his friends forming a secret society in college to protect the mortal world from hidden magical dangers. And sometimes, there are plots where Percy has a love interest who is also involved in the world of Greek mythology and they face challenges together in the college setting.
One interesting plot could be Percy and his friends going on a quest in a new, unknown realm. Maybe a place that's not part of the regular Greek mythology but still related in some way.
A great plot might involve Percy and Calypso going on a quest to save a group of demigods. Along the way, they face various monsters and challenges, and their relationship deepens as they rely on each other. They could also discover some hidden secrets about the gods during this quest.
One interesting plot could be Phoebe joining Percy on a quest. Maybe she has some unique powers that help them overcome the challenges they face, like being able to communicate with certain mythical creatures that Percy can't. This could add a new dynamic to the typical Percy Jackson quest.
Another plot could involve the Earthshaker being awakened accidentally. This causes chaos not only on Earth but also in the Underworld. Percy and his companions need to travel to different realms, including the Underworld, to figure out how to put the Earthshaker back to sleep. They encounter different gods and goddesses during their quest, and some might help while others might try to hinder them.
A cool plot could be a time - travel fanfiction. The Minotaur travels back in time to the era when the gods were more actively involved in the mortal world. He could interact with the gods, and Percy has to follow him through time to stop him from causing chaos. This would involve Percy having to deal with different rules and powers in the past, and also understanding the Minotaur's motives for going back in time.
One interesting plot could be where the NPU (assuming it's some new power or entity in the Percy Jackson universe) is a key to unlocking an ancient prophecy that no one knew existed. Percy and his friends have to figure out how to use the NPU to their advantage while also dealing with the usual monsters and gods trying to stop them.
One interesting plot could be the crossover of characters from 'Percy Jackson' and 'The Selection' universes. Maybe Percy finds himself in the world of 'The Selection' and has to deal with the different social and political structures there while still having his demigod powers.