There could be various fanfictions. Maybe some that focus on alternative endings, like ones where certain characters survive who didn't in the original. For example, a fanfiction where Erwin survives and leads the Scouts in a different way.
One way is to check on popular fanfiction websites. Look for ones with high ratings and a lot of reviews. For example, Archive of Our Own (AO3) has a large collection of AOT fanfictions. You can search for the most popular ones there.
Definitely not. AOT is a work of fiction that combines elements of fantasy, action, and drama. It's set in a made-up world with its own unique plot and characters.
The AOT manga has finished. It wrapped up all the major plotlines and provided a conclusion to the story that fans have been following for a long time.
The AOT manga has indeed come to an end. The story concluded with the last chapter, bringing closure to the series. However, fans' reactions to the ending have been quite diverse.
Not necessarily. While AOT is highly popular and has many merits, whether it's peak fiction varies from person to person. Different people have different standards and preferences for what constitutes peak fiction.
Yes, there might be. The Naruto and Attack on Titan fandoms are both huge, and fans often like to cross over their favorite characters in fanfiction. So it's quite possible to find Eren - from Attack on Titan - in Naruto fanfiction. However, it may not be as common as fanfictions within each respective universe.