One idea could be that the alien technology from Roswell somehow finds its way to Smallville. The kryptonite in Smallville could have an unexpected reaction with the alien biology from Roswell. Maybe the characters from Roswell come to Smallville in search of a new energy source and end up getting involved with the local mysteries and the Kents.
Lex Luthor and Michael from Roswell would make for an exciting duo. Lex is always looking for power and knowledge, and Michael is a bit of a rebel alien. Lex might see Michael as a way to gain access to the alien technology from Roswell. Michael, on the other hand, might be suspicious of Lex but also intrigued by his resources. Their interactions would be full of tension and power plays.
The ability to reimagine character relationships is also unique. Characters who might not have interacted in their original shows can form new alliances or rivalries in smallville crossover fanfiction. For instance, a character from Smallville could have a completely different relationship with a character from 'Supergirl' in a crossover. This gives fans a chance to see their favorite characters in new lights and explore different emotional arcs.
I really like 'Crossroads of Krypton and the Hunting Life'. In this fanfiction, the writers did an amazing job of bringing in the mythology of Smallville and Supernatural. Dean and Sam Winchester end up in Smallville and get involved with Clark's world. It's full of action and some really cool character moments. It shows how the different powers and skills of the characters from both shows can work together or clash in interesting situations.
I really liked a fanfic called 'Power Convergence'. In this story, the Charmed Ones end up in Smallville and they have to figure out how to get back home. Along the way, they meet Clark and his friends. It's a great read because it shows how the different power dynamics from each show would play out when the two worlds collide.
A crossover with 'Stranger Things' would also be cool. The kids in Hawkins could encounter the Roswell aliens. The Roswellians' advanced technology might help the kids fight the Upside - Down monsters, or perhaps there would be some miscommunication at first due to their different worlds and concepts.
The clash of different mythologies. Smallville has its Kryptonian and small - town - hero story, while Supernatural has demons, angels, and hunters. When these two collide in a fanfic, it creates a really unique and exciting world. For example, seeing how Clark's superpowers interact with the magic and weapons of the Winchester brothers.
One key element is the character interactions. Seeing characters like Clark Kent and Oliver Queen interact, given their different backgrounds and powers, is really exciting. Another element is the merging of storylines. For example, how the threats in Smallville might be related to those in the Arrowverse.
A common theme is the clash of two different worlds. Smallville is more of a small - town superhero origin story, while Buffy deals with the supernatural in a more urban and 'chosen one' kind of way. So, the fanfics often explore how these two concepts collide.
The unique combination of two very different fictional universes. Smallville has a more down - to - earth, small - town feel with its own set of superpowered characters, while the Avengers are a big - city, global - scale superhero team. When they cross over, it creates new and unexpected storylines.