One thing I've noticed is that romance-driven AUs absolutely dominate the conversation in most TV show-based fandoms. You can barely scroll through Archive of Our Own without tripping over a coffee shop AU, a university AU, or a soulmate AU. I think it's because TV characters are already so vividly realized—we've spent hours with them, we know their chemistry, their tensions. So we want to drop them into a world where those tensions can resolve in a different, often softer, way. For shows that are already high-stakes like 'The Witcher' or 'Supernatural', a modern-day, no-monsters AU feels like a cozy blanket. Maybe we're just tired of the main plot's trauma and want to see them happy.
It's not just about shipping either, though that's huge. Found family is another massive genre that crosses over with romance and gen. Think 'Stranger Things' or 'Our Flag Means Death'—the source material gives you a group dynamic that fans immediately want to explore, expand, and sometimes fix. Canon might kill off a beloved character or leave a relationship underdeveloped, so fanfiction steps in to create the catharsis the show didn't provide. I'm always more drawn to these character-driven explorations than, say, plot fix-its, which feel a bit more mechanical.