Deviantart allows nsfw content, including fetishes and gore. I haven’t seen scat so far nor do I ever want to and they don’t allow explicit penetration. Not sure about penises.
Patreon allows nudity but not ‘porn’. We consider nudity to be softcore but whatever. Anyway drawing characters naked is fine, but not any sort of fetishes. They might still be around but if its like YouTube, it’s not because they let it slide but because they haven’t removed it yet. Of course, if they found out, the artist will have to suffer a penalty of needing to remove content from external sites outside of patreon, which I think it’s stupid. No one would associate patreon with whatever they want to distance themselves from and nobody cares.
Youtube, um, I’ll say they care enough about guidelines but they are doing a slow if not horrible job of maintaining them. And of course, nudity and porn are top priority than hate and abuse of course.
Pixiv, probably the most lenient site but it’s domain is Japan. Create anything but you are recommended to censor. I say ‘recommended’ because I’ve seen uncensored stuff sometimes especially from non-Japanese artists. Either they think they are the exception as they’re not Japanese or the mods haven’t told them yet.
Anyway those are examples, feel free to expand on it.