The Void could be a place where time doesn't exist in the normal sense. Gumball and his family get separated and they each experience different slices of time from Elmore's past, present, and future. They must reunite and figure out how to escape this time - warped Void.
One idea could be an OC who has the ability to time - travel and they use it to prevent a major disaster in Elmore. Another could be an OC that is a new student at school and has a unique power that challenges the status quo among the main characters. Maybe an OC that is a magical creature trying to blend in with the normal residents of Elmore.
A crossover with 'Steven Universe' would also be cool. Gumball and Steven could bond over their unique family situations. They could have to use the power of friendship, Gumball's wacky schemes, and Steven's gem powers to defeat a common enemy, like an evil gem who wants to turn Elmore into a gem colony.
One idea could be that Gumball and his friends find a way to communicate with the zombies and try to co - exist. Maybe they discover that the zombies are not as mindless as they seem and have their own stories.
Well, they could be part of a mystery where strange things are happening around Elmore. Gumball, with his typical comical and curious nature, teams up with Carrie. They start to investigate and find out that it's related to an ancient curse. Along the way, they learn more about each other's worlds and grow closer as friends while trying to break the curse.
A lemon fanfic could also focus on a character's backstory that has never been fully explored in the show. For instance, we could learn more about Darwin's life before he was adopted by the Watterson family. This could add depth and new perspectives to the character and the overall 'Amazing World of Gumball' universe.
One idea could be a crossover with 'Adventure Time'. Gumball and Finn could go on a wild adventure together, facing challenges in a mixed - up world of both shows. Maybe they have to find a magical item that got lost between their universes.
One plot idea could be that Gumball loses his braces and has to go on a wild adventure to find them before his next orthodontist appointment. Maybe they got accidentally mixed up with Darwin's fishbowl accessories and are now at the bottom of the ocean.
One idea could be a human getting stuck in Elmore and having to adapt to the wacky rules and creatures there. For example, dealing with Gumball's crazy family dynamics.
One interesting plot idea could be an OC (original character) who comes from a different dimension and has unique powers that disrupt the normal order in Elmore. For example, they might accidentally freeze time or make everyone speak in rhymes.
They could find a source of energy in The Void. Maybe there are strange crystals that emit a life - giving force. Gumball and his friends figure out how to harness this energy to stay alive.