Well, in a Stargate SG1 and NCIS crossover fanfiction, there could be a situation where an alien artifact is found at a crime scene that NCIS is investigating. The SG1 team is then called in to figure out what it is. Daniel Jackson could start rambling about the historical and alien significance of the artifact, while Abby from NCIS is trying to analyze it from a forensic perspective. It would be a great mix of science - fiction and crime - solving elements.
One of the most interesting storylines could be a situation where the technology from Stargate SG1 somehow finds its way into the NCIS world. For example, a Goa'uld symbiote might be discovered during an NCIS investigation on a military base. The NCIS agents, being used to normal criminal investigations, would be completely out of their depth dealing with alien technology and the threat of a parasitic alien life form. This would force them to team up with the Stargate SG1 team who have the expertise in dealing with such threats.
If we consider a crossover, the NCIS characters would be in awe of the technology the SG1 team uses. Ziva would be interested in learning some of Sam's self - defense moves. And McGee would be like a kid in a candy store around all the alien tech. On the other hand, the SG1 team would have to adjust to NCIS' strict protocol. For example, Jack might find it a bit stifling at first, but he'd also see the value in it. The interactions would be full of cultural clashes and mutual learning experiences.
The characters would interact in very interesting ways. For instance, Jack O'Neill from Stargate SG1 is a military man with a sarcastic sense of humor. He would probably find Gibbs from NCIS to be a kindred spirit in terms of military discipline, but their leadership styles might clash at times. Gibbs is more about leading by example and getting his hands dirty in investigations, while O'Neill has to deal with leading a team on dangerous off - world missions.
One common theme is the clash of different cultures. In SG - 1, there are various alien cultures, and in NCIS, there's the military and law - enforcement culture. When they cross over, seeing how these cultures interact is a big part of the story. For example, how the NCIS agents react to the advanced technology and strange alien customs from SG - 1.
I like 'Buffy in the SGC'. In this fanfic, Buffy is somehow transported to the Stargate Command. The author does a good job of showing how Buffy's slayer skills are both useful and a bit out of place in the military - science - fiction setting of Stargate. There are some really cool fight scenes against Goa'uld with Buffy leading the charge.
Well, character consistency is key. The characters from SG1 should act like they do in the show. Also, a good crossover will blend the different universes or shows' lore smoothly. For example, if it's a crossover with Stargate Atlantis, how the technology and cultures interact is important.
The popularity of Stargate SG - 1 crossover fanfiction lies in the ability to combine different fictional universes. Fans love seeing their favorite SG - 1 characters in new and unexpected situations with characters from other shows.
Some of the best Smallville and Stargate SG1 crossovers involve character interactions. For instance, Lex Luthor could get involved with the NID from Stargate SG1. This could create a whole new dynamic of power - hungry characters vying for control over alien technology. It makes for a really exciting read as the two universes collide in unexpected ways.
One interesting story could be about the characters from NCIS and SG - 1 teaming up to solve a mystery that involves both Earth - based crimes and alien technology. Maybe they have to track down a stolen alien weapon that is being sold on the black market on Earth.
A third one is 'NCIS Meets Stargate SG - 1'. This one focuses more on the cultural clashes between the military - like NCIS - and the more science - focused Stargate teams. The NCIS agents are initially skeptical of the Stargate technology but as the story progresses, they learn to work together and rely on each other's skills to solve a mystery that spans across galaxies.