A crossover with 'The Powerpuff Girls' could also be cool. The villains from OK KO's world team up with some of Townsville's baddies. OK KO, along with Blossom, Bubbles, and Buttercup, have to put aside their differences in fighting styles and personalities to save both their cities. They'd learn from each other's strategies and form an unbeatable team.
One idea could be a crossover with another popular animated show like 'Steven Universe'. OK KO could end up in Beach City and have to team up with Steven to fight off a new type of gem - infected villains. They'd combine their unique powers, like OK KO's power fist and Steven's shield, to take on the bad guys.
One idea could be an OC who has a unique power related to time manipulation. They could accidentally freeze time in the plaza and have to figure out how to unfreeze it without causing chaos. Another plot could involve an OC from a different dimension coming to Lakewood Plaza Turbo and trying to adapt to the strange rules and heroes there. Maybe the OC has a power that is considered a curse in their own dimension but could be useful in Ok Ko's world.
One possible plot idea could be that Ko and Dendy team up to face a new super - villain in the city. They might start off with some misunderstandings, like Ko thinking Dendy is too bossy with her scientific approach, but then they realize they need each other's skills to defeat the villain.
A crossover with Adventure Time would also be cool. Ok Ko could end up in the Land of Ooo. He might team up with Finn and Jake to battle some sort of evil force that threatens both the plaza and Ooo. They could exchange their different fighting styles, like Ok Ko's formal karate training compared to Finn's more improvised sword - fighting.
Perhaps OK KO travels to Steven's universe and is amazed by the different types of gems and their abilities. He could learn from Steven about gem culture and in return, teach Steven some of his cool fighting moves. This could lead to them going on an adventure together to help a group of gems who are in trouble.
One common theme is friendship. Just like in the show, fanfictions often explore the relationships between KO, Rad, and Enid. They might go through challenges that test their friendship, but in the end, they always come out stronger.
Definitely Enid from 'OK KO let's be heroes'. She has her own unique fighting style and a cool personality. In a crossover, she could team up with characters like Dipper from 'Gravity Falls'. Dipper's knowledge of the supernatural and Enid's combat skills would make for an interesting duo.
I also like 'Villain Redemption in OK KO'. This fanfiction focuses on some of the villains in the show and gives them a chance at redemption. It shows a different side to them and explores their backstories in a way that makes you see them in a whole new light. It's a really cool take on the OK KO universe.
One possible plotline could be Enid dealing with the challenges of pregnancy while still trying to be a hero. She might struggle to balance her superhero duties with her physical condition. For example, she could be worried about putting herself and the baby in danger during battles.
A possible plot could involve a gem experiment gone wrong that creates a threat that spans both universes. Steven, being an expert on gem-related things, and KO, who is always ready to save the day in his world, join forces. They meet at a neutral zone between their worlds, which is being affected by the chaos. Together, they have to find the source of the problem, which is a gem - machine hybrid that is sucking the energy from both universes. They encounter various challenges on their journey, like dealing with gem traps andobox security systems. Along the way, they also make new friends from both universes who help them in their quest to stop this hybrid threat.
There could be a fanfiction where Carol and Enid go on an adventure together in the world of Ok Ko! Let's Be Heroes. Maybe they discover a new power that has a lemon - like essence. They could face challenges and their friendship could grow stronger through it all.