I don't know if it quite fits the bill as taboo, but impregnation/pregnancy is always my favorite. Especially when it's incest impregnation. Then it's definitely taboo
It used to be 95 but that site has become trash. I had stumbled upon atf early on I'm my VN journey but I didn't really know how to navigate forums yet so I might swing by again and give it another chance
I'm absolutely loving this game. I have a tendency to not read all the tags before diving into a new game so I definitely thrown for a bit of a loop when it suddenly turned into vampires when I was for some reason expecting some secret organization or something like that