Perhaps Tony is alive far from home and he discovers a parallel version of Earth in this far - off place. He finds that some of the people he knew on his Earth are there too, but with different personalities or fates. He gets involved in a power struggle between different factions in this parallel world. He has to use his skills and the technology he has with him to tip the balance in favor of the good side and also figure out how to return to his own world.
A plot could involve Tony being alive but stranded far from home. He starts to build a new life in this strange place. He befriends some local creatures or beings that are initially hostile but he wins them over with his charm and intelligence. He could also face a threat from another group in this new place that wants to use his knowledge for their own evil purposes. So he has to outwit them while also trying to find a way to contact Earth and let his loved ones know he's alive.
His character would likely become more self - reliant. Without the support system he had at home, he'd have to rely on his own wits and skills more. He might also become more empathetic as he encounters different cultures and beings far from home. For example, if he meets a species that is suffering due to a lack of resources, he may be more inclined to help after his experiences.
Perhaps in the fanfiction, Tony Stark had a secret plan for Spider - Man before his death. This plan gets revealed during the events of Far From Home and it changes the course of Peter's actions. He has to decide whether to follow Stark's plan completely or adapt it to his own style of heroism.
A really interesting plot might be that Peter and Michelle are separated from the rest of the group during a mission in a foreign country. They find themselves in a small, remote village where they discover a hidden ancient power. This power is being hunted by a secret organization. They have to protect it while also finding a way to contact their friends and get home. Along the way, they learn more about each other and their relationship deepens.
Another interesting plot might be a love triangle between Peter, MJ, and a new character. This new character could be a fellow superhero or a civilian with some special abilities. It would add a whole new layer of drama to Peter's already complicated life as Spider - Man, and force him to make some tough choices about his relationships.
One idea could be that the Avengers secretly follow Peter Parker during his European trip in 'Far From Home'. They want to make sure he can handle the new threats on his own but end up having to step in at a crucial moment. Another could be that they get caught in the same illusions as Peter and have to fight their own mental battles while trying to protect the civilians.
A great plot for a Spider - Man after Far From Home fanfiction could be that an alien race comes to Earth believing that Spider - Man is a threat to the universe because of the events in Far From Home. Peter has to prove his innocence while also protecting the Earth from this new threat. Along the way, he discovers new powers within himself and has to learn how to use them quickly. He also has to deal with the media frenzy that still surrounds him, and his relationships with his friends like Ned and MJ are put to the test as they try to help him in different ways.
A plot could be that MJ and Peter get separated from their class during a trip. They have to find their way back while also facing some villains from the Far From Home universe. MJ uses her wits to outsmart the bad guys, and Peter uses his powers to protect them.
One interesting plot idea could be Peter and MJ getting lost in a foreign city during their school trip. They have to rely on each other and their Spidey - skills (Peter's) to find their way back. Maybe they encounter a local villain who is causing trouble in the city and Peter has to secretly stop them without revealing his identity to MJ.
In a Tony Stark - related Spider - Man Far From Home fanfiction, Peter Parker could be struggling with living up to the legacy of Stark. He constantly compares himself to Iron Man and tries to use the knowledge and resources Stark left for him in a way that would make him proud. This internal struggle could be a major theme as he faces the challenges in the movie's plot.
One common theme is the relationship between Peter Parker and MJ. Fanfictions often explore their relationship further, like their adventures together outside of what we saw in the movie. For example, they might go on a road trip and face some new challenges.