Last-Name Basis/Newspaper Comics

In Bloom County and its sequel strips, Michael Binkley is simply "Binkley" to everyone else. Including his own father.
Thimble Theatre: (J. Wellington) Wimpy
Candorville notes the Double Standard in one strip from the 2008 U.S. presidential election sason, pointing out that the news always talked about "Obama and Hillary" instead of "Obama and Clinton."
- This may be justified, however, by the fact that there's only one Obama anyone would have been talking about, while "Clinton" could also mean Bill Clinton.
Schroeder from Peanuts is consistently known as such; we never find out his first name. It's an especially odd case, since early strips show that the other characters were on a First-Name Basis with him when he was a baby, before he could even talk. He picked up the piano and became the great musician he is today after he'd been called "Schroeder" for months.