The sites are mostly from places that didn't sign the international copyright conventions.
Others do everything they can to give you "benefits" but those benefits are basically by giving them your IP or by giving them exclusivity. ToS are tricky.
Some ToS prevent you from taking certain legal actions against the site.
You can still bring legal action against the site but it all depends on the laws of your state (if you live in the US) or the laws of your country.
My cousin unknowingly signed or more like accepted not being able to sue an international company that had a Ponzi Scheme. It also had many downsides which I forgot when I read it I couldn't beleive it. She basically lost all her money she had invested and she agreed, unkowingly, to do many things for the company. (Just remembered that one of those things was to sell a minimum amount per month and if she didn't she had to use her own money)
I do not have a list of all sites that are predatory but I do have a link explaining some of them. https://writerunboxed.com/2022/06/24/reading-between-the-lines-the-predatory-contracts-of-serial-reading-writing-apps/
It is hard to pinpoint companies with these practices as most are unknown in general while others don't apply to comic/novel creators instead they apply to programmers and other type of creators (if you want to see it that way).
I once refused a job offer from a trustworthy company for the sole reason that if the employee invented something then said employee would get the patent under their name but all royalties would be given to the company. The company had a decent pay but I don't think it's fair that they stay with all your royalties for a code/machine you made while you only got the patent in "name" only but with 0 benefits.
Returning to topic, like I mentioned before many things in ToS aren't legal while others are but it all depends on the laws of your local residence. If you do accept all ToS then you will have to hire a lawyer to see if you can get out of any legal binding you may be subjected to.
But overall I recommend saving your money and time (if the company is international without offices in the US then you are fighting a battle with no winners) by simply reading all ToS and investigating the site before posting anything of your intelectual property.
That's the tricky part of international companies especially online. Even if you want to sue them it could take months or even years and there is no gurantee that you will win the case as there is no international police.
