Here is an excellent article exploring the variety of typewriter typefaces used in graphic design.
"This notion of using alternate typewriter typefaces sparked my interest in many ways. I began to think about how I only wished that making typographic selections were that simple and hands on (a sort of no-nonsense approach to typography). One of the things that I became most curious about was the names or types of custom typewriter typefaces that had been used during the height of typewriter technology and how many typefaces were commercially available to typewriter owners."
It is also posted on the Walker Art Centre's design blog, which is full of amazing projects and links.