The only example I can think of is HN. It's probably the only example I can conceive of existing, too, since it's in a pretty unique position of being cheap to

The only example I can think of is HN. It's probably the only example I can conceive of existing, too, since it's in a pretty unique position of being cheap to serve and indefinitely funded (hence not under pressure to grow, monetize, or advertise to cover costs).