Well, a plot could involve a magical artifact that is causing chaos in the world. Robin discovers it first but realizes he needs Wonder Woman's help to contain it. As they work together, they start to understand each other's strengths and weaknesses more. Maybe there's also a sub - plot where some villains are trying to stop them from getting to the artifact, leading to some intense battles.
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.
A really cool plot could be set in an alternate universe where Robin has some new powers and Wonder Woman has lost hers. They have to find a way to reverse the situation. Robin uses his wits and new abilities to protect Wonder Woman while they search for a solution. Along the way, they face challenges that test their friendship and loyalty, and they also learn about the true nature of power.
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.
A possible plot could involve a mind - control situation. An evil sorcerer manages to put Robin under his spell and sends him to attack Batman and Wonder Woman. They are reluctant to fight Robin but have to find a way to break the spell without harming him. Meanwhile, they also need to stop the sorcerer from using Robin to carry out more devious plans, like stealing secrets from the Justice League.
A plot could revolve around a mystery in Gotham that seems to be related to Raven's dark magic past. Robin, being the detective he is, teams up with Raven to figure it out. Along the way, they discover that there are forces trying to use Raven's powers for evil in Gotham. They have to not only stop these forces but also deal with their growing feelings for each other, which they initially try to hide.
One idea could be a story where Nightwing has to train Robin in a new and dangerous combat technique. They could face off against a powerful new villain in Young Justice that specifically targets their mentor - protégé relationship.
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.