I swear every other Damian Wayne x reader fic I stumble across on Tumblr runs on the same battery of tropes, but it’s honestly part of the appeal at this point. You’ve got the classic 'touch-starved Robin' angle, where Damian recoils from any physical contact until the reader is somehow, patiently, allowed to brush his hair or hold his hand. It’s about that slow thaw, which works because he’s such a little fortress of trauma and training.
Another huge one is the arranged marriage trope, often for political alliance between the League of Assassins and some other fictional royal house. It’s a neat way to force proximity and watch the disdain turn into grudging respect, then something more. I’ve also seen a ton where the reader is a civilian who accidentally stumbles upon him injured on a rooftop, and their utter normality is what cracks his shell. It’s the ultimate fantasy of being the one person he doesn’t have to be a weapon around.
Lately there’s been a surge in ‘Damian Wayne & the Art of Pet Adoption’, where the reader works at an animal shelter and he keeps showing up, initially for ‘reconnaissance’ but really to adopt every stray cat in Gotham. It’s soft, it’s funny, and it lets him be protective in a non-violent way. The tropes are familiar, but the execution in the little tags and asides is where the real personality shines through.