One great storyline could be where the BAU team is called in to profile a suspect who has a connection to some strange Stargate - related technology. Maybe the suspect is using alien tech from the Stargate universe to commit crimes in the Criminal Minds world. For example, a device that can manipulate minds, which makes it very difficult for the BAU to figure out the true motives.
Well, Spencer Reid from Criminal Minds would probably be fascinated by the technology from the Stargate universe. He'd be constantly asking questions and trying to understand the scientific principles behind it. Meanwhile, Colonel Jack O'Neill from Stargate might find Reid a bit of an oddball at first, but would grow to respect his intelligence.
One great example could be a story where the characters from Psych have to team up with the BAU from Criminal Minds to solve a serial killer case that has elements of both the light - hearted mysteries Psych usually deals with and the dark, psychological ones Criminal Minds is known for. For instance, the psychic 'abilities' of Shawn Spencer from Psych could be used in an unexpected way to help the BAU profile the killer.
One great example could be a story where the Winchester brothers from 'Supernatural' team up with the BAU team from 'Criminal Minds' to hunt a supernatural - themed serial killer. Maybe the killer is using some dark magic to commit murders and leave no trace in a normal way, so both groups' expertise are needed.
A great Sherlock and Criminal Minds crossover fanfiction often has well - developed characters from both shows. The writers need to capture the essence of Sherlock's deductive skills and the profiling abilities of the Criminal Minds team. For example, a scene where Sherlock and Reid exchange ideas about a case would be really interesting.
Well, a great fanfiction storyline could involve Reid and Morgan going undercover together. Maybe they have to infiltrate a criminal organization. Reid could use his knowledge of psychology to manipulate the criminals from the inside, while Morgan uses his combat skills to keep them safe. It could also be a story where they are dealing with the aftermath of a traumatic case that has affected them both in different ways, and they help each other heal.
One idea could be that the BAU team is called in to investigate a series of strange disappearances that seem to be related to a haunted location that Teamiplier has explored in one of their videos. The two groups initially clash due to their different approaches, but then they start to work together and combine their skills to solve the mystery.
Maybe in the fanfiction, a member of the CSI team has a personal connection to a case that the Criminal Minds team is investigating. This could lead to some intense emotional moments and also some friction between the two teams as they try to balance the need for objectivity with the personal investment. The story could explore how they overcome these challenges and solve the mystery behind the crimes.
One idea could be that the Scooby Gang from Buffy teams up with the BAU from Criminal Minds to solve a series of murders that seem to have a supernatural and a psychological aspect. Maybe the murders are being committed by a demon that is using human psychological weaknesses to target its victims.
One possible storyline could be Derek's struggle to recover both physically and mentally after being shot. His team members might be deeply affected and rally around him, with each dealing with the trauma in their own ways. For example, Reid could struggle with guilt for not being able to prevent it, while Garcia would be constantly by Derek's side, using her tech skills to help find the shooter.
There are fanfictions where the advanced technology of Stargate is introduced into the Smallville universe. For instance, imagine the Langarans sharing their medical knowledge with the Smallville doctors. This could lead to some interesting character development as the Smallville characters have to adapt to new ways of thinking. Also, a crossover could explore how the alien races from Stargate would react to a being like Clark Kent with his superhuman abilities.