In a Stargate Babylon 5 crossover fanfiction, a possible plot could revolve around a mysterious energy source. This energy source could be something that is of great interest to both universes. Scientists from Stargate and Babylon 5 could team up to study it. However, different factions within each universe may have different ideas about how to use this energy. This could lead to internal conflicts as well as conflicts between the two universes. It would be a story full of political intrigue, scientific discovery, and adventure.
A possible fanfiction could revolve around a joint mission. The races from Babylon 5 and the teams in the Stargate universe come together to face a common threat. Maybe an ancient evil that has the power to destroy both their worlds. They would have to combine their knowledge and resources, like the Psi Corps abilities from Babylon 5 and the Ancient technology in Stargate.
John Sheridan from Babylon 5 and Jack O'Neill from Stargate could make an interesting pairing. Sheridan is a strong leader and diplomat, while O'Neill is a military man with a sense of humor. They could learn a lot from each other. Another could be Delenn from Babylon 5 and Samantha Carter from Stargate. Both are intelligent women with different areas of expertise. Carter in science and technology, and Delenn with her spiritual and political knowledge.
One challenge is getting the lore right for both universes. Each has its own complex set of rules, technologies, and species. For example, the Babylon 5 universe has the Vorlons and the Shadows, and the Stargate universe has the Goa'uld. Keeping all these elements consistent is difficult.
Well, in Roswell Stargate crossover fanfiction, there might be a plot where the characters from Roswell get involved in Stargate missions. Imagine the Roswell gang having to deal with the Goa'uld or the Replicators. It could also be about how the technology from Stargate affects the lives of the Roswell aliens. For instance, the Stargate could be a way for them to find a cure for their alien - related problems or a means to enhance their powers.
One idea could be that the Spartans from Halo are sent through a Stargate to an unknown planet in the Stargate universe. They have to team up with the SG teams to fight off a common enemy like the Flood that has somehow spread to that planet. Another could be a scenario where the technology from both universes is combined. For example, the Covenant's energy shields are integrated with the Stargate's shield technology.
One interesting idea could be the interaction between the different alien species from both universes. For example, seeing how Vulcans from Star Trek would interact with the Minbari from Babylon 5. Maybe they would exchange knowledge on logic and philosophy.
One idea could be that the Stargate team discovers a world where the Sentinel abilities are a natural part of the population. The Sentinels' powers could be used to help the Stargate team in their exploration and battles against alien threats. For example, their enhanced senses could detect hidden Goa'uld symbiotes or hidden traps in ancient ruins.
One idea could be to cross Stargate Universe with Stargate SG - 1. Maybe the Destiny crew discovers an ancient technology that was originally developed by the SG - 1 team on Earth. This could lead to a joint mission where both crews have to work together to unlock the secrets of the technology and use it to save both their ships and Earth from a new threat.
Maybe a character from Stargate, say Daniel Jackson, gets stranded in the Farscape universe. He could use his knowledge of ancient cultures and languages to help the Farscape crew with some of their own mysteries. And in return, the Farscape crew could teach him about their unique technology and ways of survival in a very different and often hostile galaxy.
One idea could be a crossover with Star Trek. Imagine the Stargate team traveling through a wormhole and ending up in the Star Trek universe. They could interact with the Federation, learn about their technology like the warp drive, and perhaps even help solve a crisis together.