One idea could be that there's a mystery surrounding a powerful artifact. Robin and Girl Wonder have to race against other villains and heroes to find it first. The artifact could have the power to change the balance of power in the Young Justice world. Their journey to find it could involve a lot of clues, puzzles, and battles.
Perhaps there's a fanfic where Robin and Girl Wonder accidentally swap their minds. This would lead to a lot of comical situations as they try to act like each other while also trying to figure out how to reverse the situation. But it could also have some deeper moments as they understand each other better through this strange experience.
Maybe there's a plot where they have a misunderstanding at first. Robin thinks Wonder Girl is too reckless in battle, while Wonder Girl believes Robin is too controlling. But through a series of events, they come to understand and respect each other more, and in the end, they become a stronger team.
One idea could be that Robin and Wonder Woman team up for a special mission in a hidden, ancient temple. They have to solve puzzles that require both Robin's detective skills and Wonder Woman's knowledge of ancient lore. Another could be a story where Robin gets injured during a battle and Wonder Woman takes it upon herself to train him in new combat techniques to make him stronger.
One great fanfiction could be about Robin and Girl Wonder teaming up for a secret mission. Maybe they have to infiltrate an enemy base. The story could focus on their growing trust and friendship as they face various challenges together.
A possible fanfiction could focus on Wonder Girl's relationship with other members of Young Justice. For example, she might have a friendly rivalry with Superboy that turns into a strong bond as they face challenges together. This could include them training together and learning from each other's strengths and weaknesses.
One idea could be that Robin is on a solo mission in Gotham and crosses paths with Catwoman. She initially tries to mislead him, but he sees through her tricks. They end up teaming up briefly to take down a mutual enemy who is stealing valuable artifacts from both the Batcave and Catwoman's hideouts.
Maybe in the fanfiction, the harem members are all from different backgrounds within the Young Justice universe. They are brought together by their feelings for Robin. Some are heroes, some are civilians with special knowledge. Their relationships develop as they help Robin solve a mystery that threatens the entire Young Justice world. This would involve a lot of character exploration and relationship building.
Another plot could involve Robin being forced to work undercover as an assassin in a criminal organization. He has to balance his loyalty to the Young Justice and his mission to take down the organization from the inside. He might face moral dilemmas as he has to pretend to be a cold - blooded killer.
One idea could be that Robin is on a solo mission and Deathstroke is hired to stop him. Robin has to use his wits and agility to outmaneuver Deathstroke's superior strength and experience. Another could be that Deathstroke, for some reason, decides to train Robin secretly, leading to a complex relationship between the two where Robin is conflicted about learning from an enemy.
A great plot could involve Robin getting injured and Cirel having to take care of him. During this time, they have deep conversations and start to understand each other on a more personal level. This could lead to a stronger bond between them in the fanfiction.
One plot idea could be that Arsenal and Wonder Girl are on a mission together and get stranded in an alternate dimension. They have to rely on each other's skills to survive and find a way back home. Arsenal's marksmanship and Wonder Girl's super strength would be put to the test.