Well, he might find a world where magic has been completely integrated with Muggle technology. For example, broomsticks are now used for inter - planetary travel and there are magical apps on smartphones. Also, Hogwarts could be a much larger and more diverse place, with students from all over the universe coming to study.
In fanfiction, the possibilities are endless. It could be that they go on an adventure to a previously unknown magical land or face a powerful dark wizard who was thought to be defeated.
Well, it could go in many directions. They might travel to a previously unknown magical realm or encounter creatures that were only hinted at in the original series.
Perhaps he discovers that his actions in the past had far - reaching consequences that he never anticipated. In this future, the galaxy is on the brink of a new kind of disaster because of the events he set in motion as Darth Vader. He then has to figure out a way to correct the course of history, even though it's a future he's in.
They might encounter advanced technology that they don't understand at first. For example, flying cars or instant teleportation devices. Their ninja skills could be put to the test in new and unexpected ways against futuristic enemies.
In this fanfiction, Harry might see a world where magic has evolved in unexpected ways. For example, there could be new spells that are far more powerful and complex than the ones he knew. He could also find that Hogwarts has changed, perhaps with new buildings or different teaching methods. And maybe he would encounter descendants of his friends, who have their own unique stories to tell.
Perhaps he would find that the wizarding world has finally united with the Muggle world in harmony. Technology in the Muggle world could have influenced magic in strange and wonderful ways. He could be shocked to see flying cars that are now common, or houses that are built with a combination of magic and advanced Muggle construction techniques.
Well, if Harry Potter was kidnapped by Loki, it could be a total chaos. Loki might use Harry's magic for his own devious plans. Maybe he wants to take over Hogwarts using Harry's knowledge of the school's secrets. Or he could be trying to trade Harry for something valuable in the wizarding world. Another possibility is that Harry would try to outwit Loki with his own brand of cleverness and magic, leading to a battle of wits between the two.
Another scenario could be that Ginny accepts but on the condition that they go on an adventure first. They could travel around the wizarding world, visiting different magical places they've only heard about, like the hidden valleys in Romania where dragons roam, before settling down to plan their future together.
Well, if Harry Potter finds Excalibur, it could completely change the wizarding world. He might gain some new powers from the sword. Maybe he could use it to defeat Voldemort in a more epic way than with his own wand. It could also bring a new alliance between the wizarding world and some other magical beings who respect the power of Excalibur.
One possibility is that the Upside Down continues to evolve. New and more terrifying creatures could emerge, forcing the kids (now grown up) to reunite and use their combined skills once again. Maybe Eleven's powers have developed in unexpected ways, allowing her to not only move objects with her mind but also manipulate time or space to some extent.