In 'deku meets future deku fanfiction', perhaps the future Deku warns the present one about upcoming threats. He could tell him about villains he'll face in the future and how to defeat them. This would give the present Deku an edge in his battles and also in his growth as a hero.
I think Uraraka would be very excited. She has always been a big supporter of Deku. Meeting Future Deku would give her a chance to see how far he has come, and she might also get some inspiration for her own hero journey. Plus, she's a friendly and emotional character, so she'd likely be thrilled at the opportunity.
Another possibility is that a new villain emerges as a result of the time - travel or whatever mechanism brings future Deku to the present. This villain could be from a future where Deku's actions (or inactions) have led to a more dangerous world, and he travels back in time to stop Deku from making those mistakes again. However, his methods are extreme and dangerous, making him the antagonist of the story.
One possible plot could be that the future female Deku comes back in time to warn the present - day heroes about a powerful villain that will emerge in the future. So she has to convince them to take action and train harder.
Maybe in this fanfiction, Class 1 - A is on a training mission when they accidentally stumble into a time - warp and meet Future Deku. Future Deku could be a super - powerful hero, and he starts to train them in advanced techniques that they haven't learned yet. He might also share some of his future experiences with them, like the battles he has won and the villains he has faced, which would inspire Class 1 - A to strive harder in their hero training.
It could be really interesting. Maybe in this fanfic, the future female Deku has unique powers and a different personality from the original Deku. She might be more confident and assertive, using her skills to fight in a new way. The story could involve time travel, where the present - day characters meet her and are shocked by her existence.
One interesting plotline could be Deku facing a new, extremely powerful villain that challenges his understanding of heroism. Maybe this villain has a quirk that can nullify all other quirks, forcing Deku to rely on his wits and physical training rather than just his One For All power.
Well, he might learn about his future achievements. For example, he could find out if he becomes the greatest hero. Maybe his future self gives him some advice on how to deal with upcoming villains more effectively.
Uraraka is also common. Her friendship with Deku, and perhaps a budding romance in some fanfictions, can add an interesting dynamic. She could be involved in missions with Deku or be there to support him during difficult times.
The main differences are in their expressions and some minor details of personality. In the manga, Deku might seem a bit more intense, while in the anime, he's sometimes presented a bit softer.