I noticed that the Schulz Museum is going to have a new exhibit called
"Outside the Frame." It is about those characters that were never
seen in the strip but were a part of various storylines. They
mention some of the obvious ones like The Little Red-Haired Girl, The
Red Baron, and The Cat Next Door. I thought of a few more--Linus's
teacher Miss Othmar, Charlie Brown's dad the barber, Violet's dad who
was always "better" than Charlie Brown's, Peppermint Patty's teacher
who I don't think had a name, and the school building that Sally would
talk to (though I think you could see part of it). Are there any
others?