It depends. The market for porno fiction is quite niche and often faces legal and ethical restrictions. So, in general, it's not a mainstream area that sells well.
Goodreads is mainly known as a book - review platform, but it can also be a place to sell your novel ideas. You can start discussions about the type of novel you want to write, share some of your initial ideas, and engage with the community. There are also some industry professionals who are active on Goodreads, and they might be interested in your ideas.
One way is to join writing communities or forums. There, you can share your novel ideas and see if any interested parties, like indie publishers or other writers, show interest. For example, on platforms like Reddit's writing sub - forums, many writers discuss and exchange ideas, and sometimes partnerships are formed.
Online horror magazines like Nightmare Magazine or Apex Magazine are also good places for new writers. They accept submissions of horror flash fiction. Although the competition can be tough, getting published in one of these magazines can be a huge boost for your writing career. It gives you credibility and exposure in the horror writing world.