Well, it could be about the OC growing up in the shadow of Erza Scarlet. Maybe he's trying to live up to her reputation as a great wizard in the Fairy Tail guild. He might face challenges that test his loyalty and strength, just like Erza did.
It could be a dark wizard who has a vendetta against Erza and sees her son as a way to get revenge. This antagonist might try to corrupt the OC son or use him as a pawn in his evil plans.
Yes, there might be some fanfics out there with such a concept. You can try searching on popular fanfic platforms like FanFiction.net or Archive of Our Own. However, the quality and nature of these fanfics can vary greatly.
It could start with Naruto being found in the Fairy Tail world as a baby, with Erza taking him in as her own. She might notice something special about him right away, like his strong will that reminds her of herself. Then as he grows up, he starts to show signs of both ninja and magic abilities, which puzzles everyone in the guild but also makes them excited to see what he'll become.
It could be a story where Naruto grows up in the Fairy Tail world instead of the Hidden Leaf. Since Erza is known for her strict but caring nature, she would probably train Naruto really hard. Naruto might have a different set of values influenced by the Fairy Tail guild. He could also make some new friends among the Fairy Tail members and together they could face powerful enemies. His ninja way might get a new interpretation in the context of the Fairy Tail universe.
Well, the plot could involve Naruto growing up in the Fairy Tail world with Erza as his mother. He might inherit some of Erza's strong - willed and determined nature, as well as Naruto's own unique ninja abilities. Maybe he has to face some sort of threat that combines elements from both the Naruto and Fairy Tail universes.
There is definitely some. A lot of these fanfictions play around with the idea of how Erza's strong and independent personality would interact with the magical world of Harry Potter. Maybe she'd be a transfer student or get involved in some kind of international magical event that links the two universes. Some stories might also explore her relationships with the Harry Potter characters, like how she'd get along with Hermione or Ron.
Sure. A lot of fanfic writers prefer to stay away from adult - themed content. They might write about how Erza Scarlet and Erza Knightwalker could team up against common enemies. Maybe they'd write about how they learn from each other's fighting styles or how they come to understand each other's pasts better. So, it's very possible to find non - 'lemon' fanfics about them.
Goku from Dragon Ball Z. Goku's Saiyan power and his love for fighting strong opponents would mesh well with Erza. They could have a friendly sparring match at first, and then team up to face a greater threat, perhaps a powerful villain that endangers both their universes.
One plot idea could be that a group of dark mages kidnap Erza to use her as a bargaining chip against her guild. They know her strength and reputation, so they think they can force Fairy Tail to give up some valuable magical artifacts. Another could be that an obsessed fan of Erza's kidnaps her, believing that she can be 'tamed' and made to love him. This could lead to a story of Erza having to outwit this deranged individual while also trying to escape from his clutches.