Well, perhaps some of the characters from The Walking Dead, like Rick, could meet Castiel. Castiel might initially be confused by the situation but then use his angelic powers to help them. He could also try to figure out if there's a connection between the demons in Supernatural and the walkers. It could be really interesting to see how the two groups interact and learn from each other.
One idea could be that the Winchesters somehow end up in the world of The Walking Dead. They might use their hunting skills to fight the walkers in a different way than the survivors are used to. Maybe they try to find a supernatural cause behind the zombie apocalypse.
In a crossover fanfic, the angels and demons from Supernatural could be involved in The Walking Dead universe. For example, an angel might be sent to Earth to stop the spread of the undead, believing it's part of a grand plan to save humanity. Meanwhile, the demons could be taking advantage of the chaos, making deals with desperate survivors. The Winchester brothers would have to navigate this new dynamic while also dealing with the walkers.
One idea could be that the Winchester brothers from Supernatural end up in the world of The Walking Dead. They could use their hunting skills to fight off the walkers. Maybe they'd discover that the zombies are somehow related to a demonic presence and try to find a way to stop it.
One idea could be that the Winchesters find themselves in the world of The Walking Dead. They might use their hunting skills to deal with both the zombies and any supernatural elements that start to emerge in that world. For example, they could discover that a witch is causing the zombie apocalypse as part of a dark spell.
A cool 'Walking Dead Crossover Fanfiction' idea is to cross it with 'The X - Files'. Mulder and Scully could be investigating the zombie outbreak. They might find out that it's not just a normal virus but some kind of government experiment gone wrong, which ties in with the conspiracy theories they usually deal with. And the characters from 'The Walking Dead' would be skeptical at first but then realize they need Mulder and Scully's help to figure out the real cause of the zombies.
One idea could be that Bella, with her unique ability to attract vampires in her original story, has an unexpected reaction to the zombies in The Walking Dead universe. Maybe her scent or some hidden power she has confuses the zombies, leading to some comical or strategic situations for her group.
Well, perhaps the Cullens could form an alliance with a group of survivors from The Walking Dead. They could use their knowledge of the area around Forks and their skills to help each other. For example, the vampires could protect the humans at night when the walkers are most dangerous, and the humans could help the vampires during the day when they are more vulnerable. And what if Bella's special ability as a shield could be used to protect a whole group from the walkers?
You can start by looking on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms have a vast collection of fan - created stories, and you can simply search for 'Walking Dead Supernatural crossover' in their search bars.
One idea could be that some of the Sons of Anarchy members find themselves in the world of The Walking Dead. They might use their motorcycle skills to outrun the walkers in the open roads. Maybe they try to form an alliance with Rick's group, bringing their own set of survival skills like fixing vehicles and making weapons from scraps.
One popular trope is the characters from both shows teaming up to fight a common supernatural threat. For example, the Winchester brothers from Supernatural joining forces with Rick and his group from The Walking Dead to battle a horde of zombie - like demons.
Michonne and Sam Winchester would be a great pairing too. Michonne is a skilled fighter with her katana, and Sam is very intelligent and well - read. They could work together to research any possible links between the walkers and the supernatural. Sam could also help Michonne come to terms with any new, otherworldly threats they encounter.