Hmm, I have so many that I can't possibly choose just one. I'll just make a short list.
- Pregnancy/inflation/unbirthing (biiig, round bellies, basically!). I put these together because I consider them being kind of in the same category - Paws/feet - Transformation - Futa - Femboys/crossdressing
From the top of my head(look away if you don't want to see): -Pregnancy(but I despise mpreg with all my hatred) -Breeding -Sexy/Slutty Clothing -Inflation(Both cum and standard) -Female belly expansion in general
I have quite a few so it's difficult to choose my favorite. (How about going for what was first?) That could work. It would a tie between futa, furry, and partial transformations i.e. catgirls. I have no idea what came first.
Don't know if it's a fetish or just my tastes because I never look specificaly something when it comes to looking for porn. But I admit I enjoy when I found content about asians most of the time more than other types of porn stuff I look... Regards.