If you go look at Andreas’ old videos from 5-6 years ago you can see early versions of Serenity had some sort of shortcut or app specifically for 4chan, with the clover icon and everything.
There’s actually a number of projects that started this way though I don’t know of any that grew up to be as charming and interesting as Serenity OS. Katawa Shoujo is one, though I could definitely see people complaining about the games content. The Tox encrypted messenger is one but I’m not sure that ever went anywhere.
I think most of them, like Andreas, dropped the association with 4chan pretty soon after the project started to gain real traction.
I remember seeing maybe two other operating system projects on /g/dpt/, they didn't reach significant maturity but managed to animate some graphics on the screen. I remember seeing a bullet hell game engine written in lisp, I think it was called gnumako or something along those lines.
This was around 10 years ago...