One possible plot could be the Joker somehow getting his hands on a Xenomorph and using it as a weapon in Gotham. He might find it amusing to see the chaos it causes among the citizens and the police.
Well, a plot idea could be that the Joker discovers a Xenomorph egg while exploring some strange underground laboratory in Gotham. He decides to take it with him, not fully understanding what it is. Once the Xenomorph hatches, it starts to cause havoc. The Joker initially thinks it's hilarious but soon realizes he may have bitten off more than he can chew. Another idea is that an alien race sends the Xenomorph to Earth as a sort of test, and it lands near the Joker. The Joker, seeing an opportunity for chaos, teams up with the Xenomorph. As they go on their rampage, Batman has to figure out how to stop this unholy alliance. There could also be a plot where the Xenomorph infects some of the Joker's henchmen, and the Joker has to decide whether to keep them around or get rid of them, all while trying to keep the Xenomorph under some sort of control.
A possible plot could be a story where Takemi is kidnapped by an enemy in the Metaverse. Joker, of course, goes on a mission to rescue her. Along the way, he discovers that Takemi has some hidden strengths that she has never shown before. After the rescue, their relationship changes from just acquaintance to a more intimate friendship or even something more as they realize how much they mean to each other.
Well, I'm not sure of specific 'joker x xenomorph fanfic' stories off the top of my head. But you could try searching on some well - known fanfic platforms like Archive of Our Own. They usually have a wide range of fan - created stories, and you might be able to find some interesting 'joker x xenomorph' ones there.
A more light - hearted plot could be a twi'lek visiting the Naruto world for some sort of inter - dimensional vacation. They end up befriending Naruto and his friends, and they all have fun adventures together, like exploring new areas, participating in local festivals, and learning about each other's food and traditions.
One possible plot could be that Kakyoin and Jotaro come across a mysterious horse in their adventures. This horse has some special abilities related to the 'Stand' powers in 'JoJo's Bizarre Adventure'. They then have to figure out how to handle this horse and how it might be related to their mission.
Perhaps they are in a magical realm. Snow is a lost princess with the power of snow and ice, and Hope is a young wizard in training. They cross paths when Snow is being chased by an evil sorcerer who wants to steal her powers. Hope decides to help her. As they journey to find a way to defeat the sorcerer, they fall in love. Along the way, they discover new spells and magical creatures that help them in their quest.
One possible plot could be that Momoko and Onihime are from different worlds but are brought together by a mysterious force. They initially don't get along due to their different personalities and ways of life. Momoko is more carefree and energetic while Onihime is more reserved. However, as they face various challenges together, like dealing with a common enemy who wants to disrupt their respective worlds, they start to understand and respect each other. Eventually, they become close friends and their bond helps to bring peace between their two worlds.
Perhaps a plot where Ghetsis and N are forced to team up against a common enemy that threatens the entire Pokemon world. As they work together, they gradually understand each other better and form a deeper bond.
One possible plot idea could be that Naruto and Jihl Nabaat meet during a diplomatic mission. Naruto, with his charm and determination, tries to understand Jihl's motives which are initially clouded in mystery. As they interact more, they find common ground in their desire for peace in their respective worlds, despite coming from very different backgrounds.
One possible plot could be that Sesshomaru somehow ends up in the wizarding world of Harry Potter. Maybe a magical portal or a powerful spell goes wrong. He then has to navigate this new world with its own set of rules and magic, and he might encounter Harry and his friends.
One idea could be the daughter's struggle to come to terms with her father's villainous nature. She might try to break away from the Joker's influence and find her own path in Gotham, perhaps becoming a vigilante of sorts. Another could be a story where she is kidnapped by Batman's enemies to use as leverage against the Joker.