There are some nsfw games I tried out and refunded but they're all still visible in my games section. They're not downloadable, GOG detects that I don't own them and only gives an option to rebuy so why are they still there? I can't hide them either.

Is this a site change or just specific to certain games?

I am guessing, detection is automated, whereas removal is not, so may take some time to happen manually.

Or indeed it could be Free DLC related.

I think this is it. They all had a free uncensored DLC. It's showing me this message: "you don't own this base game" so these must indeed be the DLCs just stuck to my account.

Oh well, thanks for the replies.