Well, perhaps Percy could use his knowledge of the gods' weaknesses to his advantage in the pranks. Like, knowing that Zeus is afraid of being overthrown, Percy could stage a fake 'demigod uprising' just to see Zeus's reaction. Or he could play a prank on Aphrodite by making all the statues in her temple look like really ugly versions of her. This would surely get a big reaction from the goddess of beauty.
Another idea is a love story where Percy falls in love with a minor god or goddess. This could involve them having to keep their relationship a secret from the other gods because it's forbidden. The story could explore the challenges they face in their relationship and how they deal with the jealousy and interference from other deities.
One idea could be Percy having to face a new and powerful enemy that even the other gods are afraid of. He has to use his unique skills and connections to defeat it.
One plot idea could be Fem Percy having to prove herself to the gods in a series of trials. Since she's female in this version, she might face different expectations and prejudices from the male - dominated pantheon. Another idea is a love story between Fem Percy and a god, like Apollo perhaps, and how their relationship is complicated by the power dynamics between mortals and immortals.
One idea could be Percy going on a quest to find a lost artifact that has the power to control the weather in the Olympian realm. This would put him in conflict with some of the gods who want to use it for their own purposes.
Perhaps Percy is chosen by the gods to be a mediator in a great council. He has to deal with the bickering and power - plays of the gods. He uses his experiences with both the mortal and divine worlds to bring some order. Along the way, he uncovers secrets about the gods' past that could change his relationship with them forever.
One idea could be Percy having to face a new set of challenges in the world of the gods as a consort. Maybe he has to deal with the politics among the deities, like trying to broker peace between feuding gods. Another could be Percy using his new position to help demigods in a more powerful way, for example, getting better training facilities for them.
One idea could be Percy having to face a new and powerful enemy that is secretly being controlled by an ancient god who has a grudge against the Olympians. He'd have to use his unique powers and the help of his friends in unexpected ways.
One idea could be a story where Percy has to team up with a minor Greek god, like Hypnos, to defeat a new threat that's causing nightmares across the demigod world. Another could be a fanfic exploring what would happen if Percy was sent back in time to the age of the original Greek heroes and had to prove himself among them.
Well, a great plot could involve Percy being transported to the Norse realm and having to prove himself to Odin. He might have to participate in a series of trials that are designed for Norse heroes. Or perhaps he gets caught in a feud between different Norse factions and has to use his wits and powers to bring peace. He could also discover a connection between the Greek and Norse pantheons that no one knew about before.
One idea could be Percy having to face a new, powerful enemy that is a threat to his newfound position as king of the gods. This enemy could be a primordial being that has been awakened. Another plot could involve Percy trying to reform the rules among the gods, which causes a lot of internal conflict as the other gods resist change. And perhaps Percy discovers a long - lost prophecy related to his kingship that changes everything he thought he knew.