One idea could be that a strange meta - human from The Flash's world somehow ends up in Riverdale. This meta - human has the power to manipulate memories, and starts causing chaos by making the Riverdale characters forget important things about each other. Archie and his friends then team up with Barry Allen to stop this meta - human before their town is torn apart.
Definitely Betty and Cisco. Betty is a smart and resourceful detective - in - training in Riverdale. Cisco is the tech - genius in The Flash's world. Their interaction would be great as they could share their knowledge. Betty could learn about Cisco's high - tech gadgets and Cisco could be intrigued by Betty's old - fashioned detective work.
One idea could be that the characters from Riverdale somehow find themselves in the wizarding world of Harry Potter. Maybe Jughead could be a Muggle - born wizard who discovers his powers while at Hogwarts. He might write about his strange new experiences in his journal, just like he does in Riverdale.
Flash crossover fanfiction is fan - created stories that combine elements from the 'Flash' (a superhero character or related media) with elements from other fictional universes. For example, it could be a story where The Flash meets characters from the 'Harry Potter' series and they have an adventure together. It allows fans to explore new and exciting scenarios that the original creators might not have thought of.
One way it could work is if there was a time - travel or multiverse plot. For instance, Arrow characters could accidentally end up in Riverdale's time period or vice versa. They would then have to figure out how to get back while dealing with the local problems. Maybe Green Arrow has to help solve a mystery in Riverdale that's related to his own enemies in some way.
In a Riverdale and Arrow crossover fanfiction, the story could start with some sort of interdimensional rift that pulls characters from both shows into one world. Riverdale characters would be shocked by the violence and danger in Arrow's world. Meanwhile, Arrow characters might find the high school drama and relationships in Riverdale quite strange. There could be a big bad villain that only the combined skills of both groups can defeat. They would have to learn to work together despite their differences, and along the way, there could be some romantic subplots between characters from the two shows as well.
I think in 'Marvel The Flash Crossover Fanfiction', the most interesting part would be how the Flash's abilities are perceived in the Marvel universe. Since the power scales and the overall feel of the two universes are different. Maybe the Flash would be seen as an anomaly, or perhaps a new kind of hero that the Marvel characters have to adapt to. It could also explore how the Flash's speed affects time and space in a world that already has characters like Doctor Strange who are well - versed in such concepts.
One idea could be that a powerful villain threatens both their cities simultaneously. Supergirl and The Flash have to team up, and in the fanfiction, their different powers and personalities could lead to some interesting interactions. For example, Supergirl's strength and The Flash's speed could be combined in unique ways to defeat the villain.
In a Stranger Things and Riverdale crossover fanfiction, there are so many possibilities. The gangs from both shows could team up against a common enemy. Let's say a new evil entity that combines the characteristics of the Demogorgon and the Black Hood. The friendships and romances in the story could be completely reshuffled. Steve might have a fling with one of the Riverdale girls, or Nancy could become friends with Betty. And the settings could blend together, with scenes taking place in both Hawkins and Riverdale, creating a really engaging and unique story.
In some 'Riverdale Crossover Fanfiction', a crossover with a time - travel plot is really engaging. For example, when the Riverdale gang travels back in time to the 1950s and has to deal with the different social norms while also trying to get back to their own time. Also, crossovers with other teen drama shows where they have to compete in a singing or dancing competition together can be quite entertaining.