Fantasy settings open up a whole other dimension for those storylines, honestly. It's not just about the act itself anymore; the magic systems and world-building add layers of consent, power, and consequence that you don't get in modern settings.
I've noticed a few recurring frameworks. The 'cursed arousal' plot is huge—a character, often a noblewoman or priestess, gets hit with a magic spell or potion that creates an unbearable physical need, forcing her to seek out or be taken by someone she'd normally never approach. The tension comes from her fighting against her own body's betrayal. Then there's the 'monster or demi-human capture' scenario, where an adventurer gets caught by orcs, goblins, or some kind of beastfolk. The appeal there seems to be the sheer cultural and physiological alienness, plus the dehumanization of being treated like spoils of war.
A darker but popular one involves divine or royal entitlement. Think a fallen angel claiming a mortal, or a corrupt king using his right of prima nocta. The fantasy element justifies an absolute, unchallengeable power imbalance. The resolution sometimes involves the victim gaining their own magical power later for revenge or twisted companionship, which I find more interesting than a simple victim narrative.
My personal gripe is when the fantasy setting is just set dressing—like, the characters are elves but it plays out exactly like a contemporary story. The best ones make the supernatural elements central to the conflict and the character dynamics afterwards.