Another plot could involve Deadpool being hired by some shadowy figure in the RWBY world to take out a particular target. But as he gets to know the target and the RWBY gang, he starts to have second thoughts. His moral compass, which is already a bit wonky, gets even more twisted as he has to decide between his job and doing what he thinks is right in this new universe.
One idea could be Deadpool getting dropped into the RWBY universe and thinking it's some sort of crazy new mission. He starts trying to team up with the RWBY girls, but his chaotic nature constantly causes misunderstandings. For example, he might mistake a Grimm for one of his usual foes and go after it in his own wacky way, much to the confusion of the RWBY characters.
One idea could be Deadpool trying to join the Avengers in his own wacky way. He might show up unannounced at the Avengers Tower, causing chaos and confusion among the team members. Another plot could involve Deadpool being hired by a villain to disrupt the Avengers, but then he has a change of heart halfway through. Or perhaps Deadpool accidentally travels to an alternate universe where the Avengers are very different, and he has to find a way to get back while also dealing with this strange new team.
One idea could be that they team up to take on a new super - villain who has the ability to manipulate time. Deadpool's unpredictability and Spiderman's quick thinking would make for an exciting combination in this scenario.
One idea could be that they are both transported to an alternate dimension. In this dimension, all the rules are different. Deadpool's healing factor doesn't work as well, and Harley Quinn's usual weapons are useless. They have to rely on each other's skills and knowledge to find a way back home. Along the way, they meet strange versions of their friends and enemies, which adds to the hilarity and confusion.
One idea could be that Deadpool and Spider - Man team up to take on a new supervillain who has the ability to manipulate time. Spider - Man uses his quick thinking and acrobatic skills, while Deadpool's unorthodox fighting style and regeneration ability keep them in the fight.
A possible plot is that a portal opens between the Doom universe and RWBY's. Some of the Doom demons start spilling into Remnant, the world of RWBY. Ruby and her team initially mistake them for a new, extremely powerful type of Grimm. As they try to fight them, they realize they need different strategies. Meanwhile, the Doom Slayer follows the demons through the portal to stop them. Eventually, the two groups meet and learn from each other's combat styles to defeat the invading demons.
Well, a cool plot for a Witcher RWBY crossover fanfiction might involve the Witcher's magic and potions being introduced to the RWBY universe. For example, a potion that gives the RWBY characters temporary enhanced senses like a Witcher. Or perhaps a situation where a powerful Witcher villain comes to the RWBY world and the teams have to combine their skills to defeat him. The different fighting styles of the Witcher and RWBY characters would make for some really exciting battle scenes.
Well, another plot could involve Sans and Papyrus coming to the RWBY world. Papyrus might be fascinated by the Grimm and try to befriend them, while Sans could use his powers to help the RWBY team in their battles against Salem. He could also share his knowledge of timelines with Ozpin.
One idea could be the Overwatch heroes being transported to the RWBY world. They could team up with Team RWBY to fight a new common enemy, like a powerful Grimm that is immune to normal attacks but vulnerable to Overwatch tech. Another plot could involve a character exchange, where a RWBY character like Ruby goes to the Overwatch world and learns about their technology and fighting styles, and then brings back new knowledge to her own world.
One idea could be Cinder being transported to an alternate universe within the RWBY world where the roles are reversed. For example, she could find herself in a world where she is a huntress in training, facing the same challenges as the main characters but from a different perspective. Another plot could involve a team - up between Cinder and a group of RWBY characters against a common, greater enemy that threatens both their goals and the world. Maybe a new, powerful Grimm that has abilities they've never seen before.
One idea could be that the Dragonborn is somehow transported to the RWBY world. They could use their shouts to combat the Grimm. For example, 'Fus Ro Dah' could send Grimm flying back, and the local Huntsmen and Huntresses are both amazed and a bit wary of this new power.