A cool plot could be that a Sith Lord somehow discovers the existence of the Earth Defense Fleet and tries to corrupt some of its members to use their advanced weaponry for his own evil purposes. This would lead to an internal struggle within the fleet as they try to resist the Sith's influence.
Perhaps the Earth Defense Fleet could get stranded in the Star Wars universe. They then have to use their unique Earth - based technology in combination with Star Wars tech to find their way back home while also getting involved in local conflicts.
Maybe an experienced admiral from the Earth Defense Fleet. She would bring her strategic knowledge to the table when dealing with the complex political and military situations in the Star Wars universe. And she could also form alliances with characters like Leia Organa.
Maybe there's a fanfiction where a Sith Lord tries to take over Earth. The Earth's military would be no match for the Sith's powers at first. But then, through some clever thinking and the discovery of a hidden Earth - based energy source similar to the Force, they start to fight back.
One idea could be Jedi coming to Earth to train a select group of humans with Force - like abilities. Another could be a Sith Lord arriving on Earth and causing chaos, and Earth's heroes have to team up with Star Wars characters to stop him. Maybe there's a discovery of a hidden Star Wars - related artifact on Earth that has the power to change the balance of the Force.
One idea could be a story where Earthlings discover a long - lost Jedi temple on Earth. This temple holds ancient secrets and powers that could change the balance of the Force in the Star Wars galaxy. Maybe some Earthlings have latent Force - sensitive abilities that are awakened by the discovery.
Another idea is that a group of Jedi, on a mission related to the Clone Wars, end up on Earth. They discover a hidden Force-sensitive group here. Together, they work to protect this group from the threat of the Separatists who also somehow find their way to Earth.
One idea could be a human from Earth somehow getting transported into the Star Wars universe and having to adapt to the use of the Force. They might start as a complete novice but quickly learn and use their unique perspective from Earth to gain allies. For example, they could introduce Earth technology concepts to the Star Wars characters.
One idea could be that the girl from Earth discovers a hidden Jedi power within herself. Maybe she has a unique connection to the Force that no one on Earth or in the Star Wars galaxy has seen before. This could lead to her being hunted by both the Sith and the Jedi, as they are unsure whether she is a threat or a new hope.
One idea could be a crossover where characters from Earth's history, like ancient Egyptian pharaohs, team up with Jedi from Star Wars to fight against the Goa'uld from Stargate. They could combine their unique powers and technologies. For example, the Jedi's use of the Force and lightsabers along with the pharaohs' knowledge of magic and the Goa'uld's advanced weaponry would make for an exciting story.
Perhaps in the fanfiction, the technology from Star Wars is used to explore the deepest parts of Planet Earth. For example, using starships to reach unexplored caves or the ocean floor.
One interesting plot could be that the Emperor from Star Wars decides to use Earth as a testing ground for a new weapon. He sends some of his minions to Earth during WW2. The people of Earth, not understanding the true nature of these invaders, fight back. Meanwhile, a group of Jedi, who have been secretly observing Earth, decide to intervene. They train some of the bravest Earth soldiers in the ways of the Force, creating a new breed of warriors to take on the Emperor's forces. This would involve a lot of character development as the Earth soldiers learn to use the Force and adapt to this new way of fighting.