One plot idea could be that Battle Angel is sent on a mission to stop Reaper's latest terrorist act in the Overwatch universe. Along the way, she discovers that Reaper has a hidden motive related to his past in Overwatch. This could lead to a series of battles and tense encounters as she tries to figure out his true intentions.
A plot could revolve around Battle Angel being a new recruit in an area where Reaper is causing chaos. She becomes obsessed with taking him down because she has heard so many horror stories about his deeds. However, as she gets closer to him, she realizes that there is more to him than just a mindless villain. There could be a backstory about how Reaper was once a hero like the others in Overwatch, and Battle Angel starts to question if she's on the right side of the fight.
A possible plot for an Overwatch Reaper OC fanfiction could be that the OC is a new recruit in an anti - Overwatch group. Reaper is sent to deal with this threat, but discovers that the OC has a connection to his past that he had forgotten. This connection makes Reaper hesitate in his mission. Meanwhile, the OC has to decide whether to use this new - found knowledge to their advantage or try to reach out to the tortured soul that Reaper has become.
It could develop in a more complex way. Maybe Battle Angel initially hates Reaper but then discovers that he has some redeeming qualities. This could lead to a love - hate relationship. She might be attracted to his power and mystery, while still being repulsed by his actions. In the fanfiction, their relationship could be full of tension, with moments of near - reconciliation followed by sudden betrayals.
One plot idea could be that Spiderman gets transported into the Overwatch universe. He has to team up with the Overwatch heroes to stop a villain who has technology that can disrupt both universes. For example, Doomfist might be interested in using this technology to gain more power, and Spiderman's agility and unique powers would be useful in the fight.
Well, a possible plot could be that in the Naruto universe, a portal opens up and out come some of the Overwatch female heroes. Naruto, being Naruto, is intrigued and wants to help them find their way back. As they stay in his world, they learn about chakra and Naruto's way of life. In return, they teach him about their advanced technology. This interaction could lead to some romantic feelings developing among them, creating a harem - like situation. For instance, Mercy might be fascinated by Naruto's healing abilities which are different from her own and a bond could form between them.
A crossover with Ghost in the Shell could be really interesting. Alita could meet Major Kusanagi. They could exchange knowledge about their cybernetic bodies and the nature of consciousness. Maybe they'd work together to stop a hacker group that's trying to gain control over all cybernetic beings in both their worlds.
One idea could be that a fallen angel is sent to the Naruto world to retrieve a powerful artifact that has been lost there. Naruto, being the curious and heroic type, gets involved and they end up having to team up. Another could be that the fallen angel is on the run from some other celestial beings and Naruto offers her protection in his village. A third idea is that the fallen angel has some unique powers that Naruto wants to learn from to become stronger in his fight against the Akatsuki.
One plot idea could be that the Overwatch heroes are transported to the Naruto universe. They have to adapt to the chakra - based powers and the different combat styles. Meanwhile, they might also introduce some of their own technology and teamwork concepts to the Naruto characters, leading to some interesting interactions and battles.
One idea could be that they team up to face a new, powerful enemy that threatens their world. They have to combine their unique abilities to defeat it.
One idea could be that Midnight and Angel are on a mission together and they discover a hidden power that only works when they combine their magic. Another could be a story where they have to overcome their differences in magic types to save the Fairy Tail guild from a powerful enemy. Maybe they start off as rivals but gradually fall in love during their adventures.
Maybe the angel reader has the power to heal, and one of the lost boys gets injured. The angel saves his life, which then binds them in an unexpected way. The other lost boys are both grateful and a bit jealous. This leads to a series of events where the angel has to navigate the complex relationships among the lost boys while also hiding their true identity from the outside world.