A great Merlin stories fanfiction idea is one where Merlin has to go back in time to correct something that went wrong in Camelot's history. This could involve him having to face his younger self and convince his past self to make different choices, all while trying not to disrupt the timeline too much.
One great 'powerful Merlin fanfiction' could be the ones where Merlin fully embraces his magic and uses it to reshape Camelot's future. For example, in some stories, he doesn't hide his magic from Arthur as early as in the original series and they rule Camelot together with magic being an open and respected part of the kingdom.
There are some that depict Merlin as a street magician in modern London. He uses his real magic in his shows, but people think it's just clever illusions. He meets Arthur, who is a skeptic at first but then becomes intrigued by Merlin's seemingly unexplainable tricks.
One interesting Merlin and Freya fanfiction could be where they go on a journey together to find a magical cure for a plague that's hitting Camelot. In this story, they face many challenges and their relationship deepens as they rely on each other's strengths.
One interesting Merlin N17 fanfiction could be a story where Merlin uses his magic in a new and creative way to save Camelot from a hidden threat. Maybe he combines his powers with some ancient spells that were long forgotten.
There could be a fanfiction where Merlin uses his magic in a different way than in the original series. For example, he might use it to create a magical school in Camelot, teaching other young magic - users how to control their powers. This would change the whole dynamic of Camelot and its relationship with magic.
One interesting Merlin is king fanfiction could be about how Merlin uses his magic to bring about a new era of peace and prosperity in Camelot under his rule. He might introduce new laws that are fair to all, regardless of their social status or magical abilities.
Well, in some Merlin death fanfiction, Merlin might die in a battle against an ancient evil. His death could lead to a series of events where Camelot starts to crumble without his magic and wisdom. However, his legacy lives on through the people he has inspired. There are also stories where Merlin's death is foretold in a prophecy, and he spends his last days trying to prepare Camelot for the future without him.
One interesting proactive Merlin fanfiction could be where Merlin uses his magic more openly to change the political landscape in Camelot. For example, he might secretly influence laws that are unfair to the common people. Another could be about Merlin taking proactive steps to train Arthur in magic, defying the ban in Camelot. This would add a whole new dynamic to their relationship as Merlin tries to make Arthur see the value of magic in a different way.
There are fanfictions where Merlin's omega nature makes him form a special bond with the magical creatures in Camelot. This bond then helps him save the kingdom in unexpected ways. For example, he could communicate with a dragon who gives him crucial information.
One interesting Merlin and Arthur fanfiction could be where Merlin reveals his magic to Arthur in a very unexpected and comical way. For example, during a royal banquet, when a knight accidentally drops a sword that's about to impale Arthur, Merlin freezes time and casually walks over to pick up the sword, then unfreezes time and acts like nothing happened. Arthur is left completely bewildered until Merlin finally confesses his powers.