One possible plotline could be that they meet in a strange, otherworldly situation. Maybe Flash, with his super speed, accidentally runs into the Twilight universe and meets the characters there. They fall in love over time and decide to get married, facing the challenges of their different worlds and abilities.
One way to find 'Twilight and Flash get married' fanfiction is to join relevant fan communities. For example, on Reddit, there might be sub -reddits dedicated to Twilight or Flash where fans discuss and share fanfiction. You can post a request there asking for such stories. Another option is to follow fanfiction authors who are known to write about these characters. They might have written a story with this plot or could be planning to in the future.
A plotline might involve a werewolf character with blind faith in their pack's traditions. But when a new threat emerges that the traditional ways can't handle, they have to decide whether to stick with their blind faith or adapt. In the context of 'Twilight', there could also be a plot where a character has blind faith in the idea of a 'true love' that crosses the boundaries between species, like a vampire - human relationship, and they go to great lengths to pursue it, facing many obstacles along the way.
A plotline might involve Twilight Sparkle being transported to a Spartan - based realm. There, she has to prove herself in their combat trials. As she progresses, she discovers a conspiracy within the Spartan society that she has to expose using her intelligence and magic. Or perhaps she teams up with a group of Spartans to retrieve a powerful magical artifact that is of great importance to both her world and the Spartan world.
One possible plotline could be that Lucy has a hidden talent for singing, and in the Twilight world, she uses her singing to attract the attention of a certain vampire or werewolf. Maybe it creates a new kind of bond or rivalry among the supernatural beings.
One possible plotline could be that a character is using a hammer and a nail to build a shelter in the forest near Forks. This could be a survival - type story where they have to fend off vampires or werewolves while building. Another could be that the hammer and nail are used to repair a special object that has some significance in the Twilight lore, like a charm or a family heirloom.
A plotline could involve them having to deal with political or power - related issues. Since they might come from different backgrounds in the original story, their marriage could stir up a lot of trouble in the power dynamics of their world. For example, there could be factions that oppose their union, and they have to fight to stay together.
One possible plotline could be their adjustment to married life. For example, how they deal with daily chores, in - laws (if applicable in the fanfiction world), and balancing their personal and couple time. Maybe Tsukune is trying to figure out how to support Moka in her vampire - related activities while still maintaining a normal life.
In some 'Harry married Lily' fanfictions, the plot might revolve around a prophecy that was misinterpreted. Instead of Harry being related to Voldemort in the way it was originally thought, the prophecy could be related to his connection with Lily in a romantic way. This could lead to a whole new set of events where they get to know each other on a deeper level, overcome various obstacles in the wizarding society that would oppose such a relationship, and eventually get married. There could also be elements of family drama, like how James Potter would react in such a scenario, or how Harry's friends would view this relationship.
One possible plotline could be their adjustment to living together. Since they have different habits, it would be interesting to see how they adapt. For example, Dan might be messy and Runo neat, so they have to find a middle ground.
One possible plotline could be Dudley trying to keep his wife's magical identity a secret from his Muggle friends and family, leading to all sorts of comical misunderstandings.