Maybe a wizard who has the power to see all possible futures in the 'Game of Thrones' world. This wizard could try to manipulate events to prevent the destruction of Westeros, like stopping certain key characters from making fatal mistakes. They might start by interfering in the decisions of Daenerys Targaryen, guiding her in a more peaceful path to the Iron Throne.
One idea could be a wizard who uses magic to bring back characters from the dead in a way that completely alters the power dynamics in Westeros. For example, bringing back Ned Stark and having him lead an army of the resurrected against the White Walkers.
One idea could be a wizard in the North discovers a long - lost magic spell that can control the weather. This would give the North an advantage in the war against the White Walkers. Another plot could involve the wizard forming an alliance with the Starks and using magic to help them reclaim Winterfell.
One idea could be exploring what would happen if a minor character like Gendry had been secretly trained in magic. He could use his newfound powers to unite the smallfolk against the warring nobles. Another plot could revolve around a female knight from the North who disguises herself as a man to fight in the wars, and along the way, she discovers secrets about the White Walkers that no one else knows. Or perhaps a fanfiction where Daenerys and Sansa form an alliance much earlier and together they reshape the power dynamics of Westeros.
One idea could be exploring what would happen if a minor character, like Gendry, had a more central role in the fight against the White Walkers. He could lead a group of common folk and prove that the power doesn't always lie with the nobles.
A really cool 'Game of Thrones fanfiction' plot could involve the resurrection of some of the dead characters in a different way. For example, what if Ned Stark was brought back not as a vengeful wraith but as a wise advisor to a new king or queen? His honor and wisdom could shape the future of Westeros in a completely new direction. And it would be interesting to see how the other characters react to his return.
Perhaps a fanfiction where Daenerys Targaryen lands in Westeros earlier and forms an alliance with the Starks before the events of the main series. This would completely shift the political landscape and the fight for the Iron Throne. She could bring her dragons to help fight the White Walkers from the start.
One idea could be that Oliver Queen somehow gets transported to Westeros. He could use his archery skills to survive in the dangerous world. Maybe he'd join a faction, like the Night's Watch, and teach them his modern combat techniques.
One idea could be exploring what would happen if a minor character, like Gendry, became the King of Westeros. He has a claim to the throne through his Baratheon blood and his time with the Brotherhood without Banners could give him a different perspective on ruling. Another plot could involve a female character, like Brienne, leading a new order of knights that are dedicated to protecting the realm in a more democratic way. Or perhaps a story where the White Walkers and the humans form an uneasy alliance against a new, even greater threat from Essos.
One idea could be the Hound's journey after leaving King's Landing. He could encounter a group of outcasts and form an unlikely alliance to protect a small village from raiders. It would show his growth from a bitter, angry man to a more empathetic protector.
In Spartan Game of Thrones fanfiction, a possible plot is the discovery of Spartan artifacts in Westeros. A young maester finds a hidden vault with Spartan weapons and armor. He tries to understand their purpose and power. Meanwhile, a knight from a minor house gets hold of one of the Spartan swords. With it, he gains an edge in combat and becomes a key player in the power struggles, attracting the attention of the major houses and changing the course of the political and military affairs in Westeros.
One idea could be a character from a minor house rising to great power through unexpected alliances. For example, a character from House Frey who tries to redeem the family's name after the Red Wedding by allying with the Starks and helping them take back Winterfell. This would bring a new dynamic to the story as the character has to face the prejudices against their house.