The other Teen Titans could also play a big role in the rescue. Starfire could use her powers to fly in and distract Slade while Cyborg and Beast Boy create a diversion. Raven could use her magic to break any spells or traps that Slade has set for Robin. They would all work together as a team to get Robin back safely.
Yes, there are likely some out there. You can start by looking on fanfiction websites like Archive of Our Own or FanFiction.net. Just search for 'Slade hurts Robin' and you should be able to find relevant stories.
Robin would probably stay calm and observant. He's been trained well, so he'd immediately start looking for any weaknesses in his captivity situation. He might try to pick the locks on his restraints if he's bound, or find a way to communicate with his team secretly if there's a chance.
One common theme could be the power dynamic between Slade and Robin. Since Slade is often portrayed as more powerful and experienced, it creates an interesting dynamic in the fanfiction. Another theme might be the forbidden nature of their relationship, considering their different sides in the story's context.
The plot might go like this. Slade kidnaps Robin in a very stealthy way. He takes Robin to an abandoned building. There, he tries to indoctrinate Robin into his way of thinking. He could be telling Robin that Batman is using him and that he can offer Robin more power. However, Robin stays true to his beliefs. Meanwhile, Batman is on a frantic search for Robin, following every lead, and the Bat - family is also on high alert. Robin is constantly looking for an opportunity to turn the tables on Slade and escape.
In this kind of fanfiction, Robin might be in a lot of danger. Slade could be using Robin to get to Batman. He might try to brainwash Robin and turn him against his friends. For example, he could lock Robin in a secret lair and show him false information about Batman to make Robin question his loyalty.
One common theme is power dynamics. Slade is often portrayed as more powerful, and the story may revolve around how he uses that power to harm Robin. Another could be revenge, where Slade has a motive to hurt Robin for something that happened in the past.
One common theme is the power dynamic between them. Given their different natures, the exploration of who has more power in the relationship is often seen. Another could be redemption, perhaps Slade seeking redemption through his relationship with Robin.
One common theme is the struggle for control. Slade's possessiveness often leads to a power struggle with Robin who values his independence. Another theme could be the blurred lines between love and obsession. Since Slade is possessive, it can seem like his feelings cross over from just caring to being overly obsessed.