Those are good sites. But cartoon porn with underage characters is illegal in some countries. And marginally so in the US, depending on attitude of the prosecutor. Also, I've come across some cartoon porn sites that are too disturbing to even risk describing here. Violence per se isn't so illegal, but underage sex + violence may well be.
That's actually the most disturbing aspect. They're absolutely cruel and disgusting, and yet extremely sexual. And it's been very hard to forget about them.
Some old-school shock sites were a little like that. Lemon party, for example, is a disturbing image, for an old man. And that girls/cups one. But even those are just funny, compared to what I'm talking about.
If you email me, or PM me on Keybase, I'll share the link.
And on reflection, I get that what I'm talking about isn't all that uncommon. Just torture, hanging, decapitation, cannibalism, etc. Some of my favorite fiction features all of that. Burroughs, Abercrombie, Morgan, Stover, and lots of older stuff.
I know, but I'll stick to it until a proper successor appears. nhentai.net and hitomi.la recompresses images and I want to be able to archive the originals easily.
Edit: I tried visiting them without adblock and I'm actually surprised they didn't even have ads.