One possible plot could be Loki initially trying to use Tony for his own gain but then truly falling for him. Maybe Loki, in his usual sly way, gets close to Tony to access some of Stark's technology, but as time passes, he discovers Tony's charm, intelligence and vulnerability, and his feelings turn sincere.
Another plot could revolve around Loki, after being redeemed in some way, trying to fit into Tony's world. He has to deal with the Avengers' distrust of him while trying to win Tony's heart. There could be a lot of tension and drama as Loki tries to prove himself worthy of Tony's love, with Tony slowly breaking down his walls and seeing the real Loki beneath the trickster facade.
Another plot might involve the Avengers trying to figure out how to deal with de - aged Tony and Loki. They could be worried about Loki's intentions since he's usually a villain, but at the same time, they have to take care of a child - like Tony. This creates a lot of comical and tense situations.
Natasha Romanoff would be an interesting character to include. She's very perceptive and could be the one to first notice the change in Loki's behavior towards Tony. And then there's Bruce Banner. His scientific mind could interact with both Loki's magic and Tony's technology, and he could also offer some unique perspectives on their relationship, perhaps warning Tony about the risks of getting involved with Loki.
One possible plot could be that Tony, due to some external pressure or misunderstanding, gets involved with another character while in a relationship with Loki. Maybe he's forced into a political alliance that looks like cheating to Loki. Another could be that Tony's self - destructive tendencies lead him to make a mistake and cheat, causing a rift in their relationship that they then have to struggle to repair.
Maybe Vergil falls in love with a mysterious figure from a different dimension. This person has unique powers that both intrigue and attract Vergil. Their love story could involve Vergil trying to understand this new world the person comes from while also dealing with his own inner demons. As their love grows, it might also change Vergil's view of his own power and purpose.
There are fanfictions where Loki uses his magic to help Tony with some of his tech experiments. In these stories, Loki is intrigued by Tony's intelligence and the advanced technology that he has created. Tony, on the other hand, is fascinated by Loki's magic and they exchange knowledge, leading to some amazing inventions and magical - tech hybrids.
One possible plot could be Aphrodite's attempts to court Percy in a very flamboyant and over - the - top way, which causes chaos among the other gods. Another could be Percy being completely oblivious to Aphrodite's feelings at first and thinking she's just being her normal, meddling self. And there might be a plot where Aphrodite has to compete with other characters who also have an interest in Percy.
A great plot could be how their relationship affects the rest of the Dragon Ball gang. Goku might be a bit confused at first, and Chi - Chi could be either supportive or a bit jealous. And then there's the whole dynamic of Vegeta becoming more involved in Earth - based family life, which is a huge change for him.
Well, sometimes in such fanfictions, there might be a plot where Orihime gets into some kind of magical trouble. Ichigo, being the protective one, tries his best to save her. In the process, he discovers that his feelings for her are more than just friendship. For example, he might have to face his own fears and insecurities about loving her, which adds a lot of depth to their relationship in the story.
One interesting plot could be that Peter Pan falls in love with a modern - day girl who somehow ends up in Neverland. He is initially confused by these new feelings as he has always been carefree. But as he spends more time with her, he discovers a whole new side of himself. He starts to care about her safety more than his own adventures.
One possible plot could be that Elsa and Hans meet secretly. They start to share their true feelings and dreams away from the prying eyes of the kingdom. As they fall deeper in love, they face the challenge of how to make their relationship acceptable to the people who have misjudged Hans in the past.