I seem to be stepping into the lion's den here but this thread is being way too far derailed in my opinion, came here to see some nice preg art.
I can understand artists not wanting to draw certain things fore whatever reason; but if you really want specific art drawn just learn some art skills and keep practicing at them if you are thirsty enough for specific. Don't be afraid to pick up a pen and learn a specific skill, try to better yourself and you may actually enjoy it better than having others draw it for you.
I am trying to learn practice and refine art myself to draw the fetishes I personally want, mostly yuri and monster girl art, which includes preg.
That is my 2 cents.