One idea could be that a Sentinel's enhanced senses are used to detect a hidden Goa'uld base that the Stargate team has been searching for. The Sentinel could sense the unique energy signatures or the presence of the symbiotes in a way the normal technology couldn't. Another idea is to have a Sentinel character be accidentally transported through the Stargate to a different planet. There, they have to use their Sentinel abilities to survive and team up with the Stargate team members who are also on a mission there.
The main characters are likely to be a mix of the well - known figures from both the Sentinel and Stargate franchises. In the Sentinel side, Blair Sandburg might be there, given his importance in that universe. From Stargate, Teal'c could be one of the main characters. The fanfiction might also focus on some secondary characters from both universes and give them more prominence as they navigate the challenges of this crossover, like how they deal with the differences in technology and power systems.
One interesting concept could be the combination of the Sentinel's unique abilities with the technology and settings of Stargate. For example, how the Sentinel's heightened senses might interact with the alien technologies in the Stargate universe. Another could be the character crossovers, like how the Sentinel characters might fit into the existing Stargate teams and their dynamics.
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.
A Sentinel and Daniel Jackson could have some interesting interactions. The Sentinel's intuitive understanding could complement Daniel's academic knowledge. For example, when exploring an ancient ruin, the Sentinel might sense a hidden danger that Daniel's research misses. Another good interaction could be between a Sentinel and Teal'c. Teal'c's warrior skills and the Sentinel's enhanced combat abilities could lead to some intense training or fight scenes together.
For starters, you can focus on their skills. For instance, the Stargate characters' knowledge of different cultures and advanced technology can be paired with the Sentinels' unique abilities like their enhanced senses. Daniel Jackson from Stargate could study Sentinel culture, while a Sentinel could use their senses to help Jack O'Neill in combat situations.
First, you need to be really familiar with both universes involved in the crossover. For Stargate, know the different gates, the Goa'uld, and the various teams. Then, come up with an interesting premise. Maybe it's a new enemy that can only be defeated by the combined forces of the two universes in your crossover. Keep the characters true to their original personalities.
A Stargate and Battlestar Galactica crossover can also be amazing. Picture the Stargate teams dealing with the Cylons. The fanfiction often explores how the military strategies from both franchises would clash or blend. It usually has a lot of action - packed scenes as well as some deep character - driven moments.
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.
One common theme is the clash of different cultures. The Sentinel has its own set of norms and the SGA universe has a whole different set with the various alien cultures in the Pegasus Galaxy. Another theme is the exploration of new powers. The Sentinel's powers in the context of SGA's advanced technology and alien threats can lead to some interesting storylines.