I, for example, am very turned on by contrasts. So noticeable height differences, size differences (individual body parts or the whole package), skin tone, shapes, etc.
I kinda wish my wife (who’s very pale) were bi because I would love to see her have sex with a dark skinned woman that’s a similar height and weight as her, or a short, petite woman (she’s also tall for a woman).
On the subject of contrasts: You show me four women and I’d pick the one who is apparently different, every time. Three blondes and a brunette? Three brunettes and a blonde? Three sundresses and shorts and t-shirt? I’ll pick “the ___ one” every time.
Thunderstorms. I am not aroused by thunderstorms, but they’re great fucking weather. I don’t know if it’s because it’s cooler, if it’s the background noise, the lighting, but my ideal sex scenario has a summer afternoon thunderstorm going on outside.