One possible plot could be that a bio - hazard outbreak occurs in New York City. Spiderman has to not only fight the usual criminals but also deal with the infected. Meanwhile, some Resident Evil characters like Leon S. Kennedy are sent to investigate the outbreak. They cross paths with Spiderman, and at first there is mistrust, but they soon realize they need to work together to stop the spread of the virus and take down the mastermind behind it, perhaps a new villain who has combined Oscorp technology with Umbrella Corporation's bio - weapons.
Another great pairing could be Peter Parker (Spiderman) and Albert Wesker. It would be a very dynamic duo as Wesker has his own mysterious and powerful abilities. Peter, with his scientific knowledge and superhero skills, could either be in conflict with Wesker or end up having to work with him in a strange alliance to stop an even greater threat in a complex plot.
It could be that a corporation in the Resident Evil universe is secretly conducting experiments in Zootopia. They are trying to create a new type of bio - weapon using the unique genetic makeup of the animals. This causes a series of strange events in Zootopia. The Zootopia police force, led by Chief Bogo, starts to notice the unusual happenings. Meanwhile, a character from Resident Evil 7, like Mia, has some knowledge about what the corporation is up to and tries to warn the animals. In the end, the animals and the Resident Evil character join forces to take down the corporation and save Zootopia from a biological disaster.
One possible plot could be that James Heller somehow gets transported into the Resident Evil universe. He then has to team up with the Resident Evil characters to fight against a new and powerful virus that is a combination of his world's threats and the Resident Evil ones.
One possible plot could be that Naruto and his friends are transported into the Resident Evil universe. They team up with some of the Resident Evil survivors to fight against the zombies and bio - organic weapons. Naruto could use his shadow clones to distract the hordes of zombies while the others find a way to develop a cure using Naruto's chakra which has some unique properties.
One possible plot could be that Loki, in his mischievous ways, decides to play a prank on Spiderman's city. Spiderman then has to figure out who is behind all the chaos. Along the way, they start to understand each other's motives and powers. Loki realizes that Spiderman is not just a simple hero but has a strong sense of justice. Spiderman, on the other hand, sees that Loki is not just a villain but a complex being with his own story.
The plot could revolve around Michelle being in danger and Spiderman having to rescue her. This classic scenario can be spiced up by adding some twists. For example, the danger could be related to a new technology that a villain is using, and Michelle's knowledge of science becomes crucial in defeating the villain after Spiderman saves her.
The plot could be about a threat that affects both Spiderman's New York City and Artemis' domain. They meet by chance, perhaps through a magical portal. Then they have to figure out how to communicate and work together to stop the threat.
Well, the relationship between the OC and Jill needs to be developed in a believable way. It can't be too rushed. They should start with some sort of connection, like a shared goal or a common enemy. And the fanfiction should stay true to the Resident Evil universe in terms of the overall atmosphere, the types of threats, and the lore.
Survival is also a major theme. The characters in both Resident Evil and Hellsing are constantly in life - threatening situations. In fanfics, this often leads to some intense and harrowing scenes. They might be trapped in a zombie - infested area from Resident Evil while also dealing with the dangerous vampires from Hellsing, and the characters have to use all their skills and resources to stay alive.
One possible plot could be that Spiderman and Red Sonja are brought together through some sort of interdimensional rift. They initially clash due to their different fighting styles and moral compasses. Spiderman is used to protecting the city and trying not to kill, while Red Sonja is more of a fierce warrior from a different era. However, as they face a common enemy, perhaps an ancient evil that threatens both their worlds, they learn to work together. Their combined skills, Spiderman's agility and web - slinging along with Red Sonja's swordsmanship and combat experience, make them a formidable team. In the end, they not only defeat the enemy but also gain a new respect for each other's ways.