1966 Olympia SM9
Up for sale is a nice Olympia SM9 which was manufactured in 1966 in Western Germany. This typewriter is in near mint shape all around, and is fully functional right down to the bell. This typewriter features Olympia's "modern pica" font in the standard 10-pitch. Olympia typewriters have an excellent reputation for being well-built and engineered machines, and this one is no exception. The SM9 is one of my favorite portables to type with, and so I would highly recommend it for heavy typing- even for heavy duties such as novel-writing.
Universal ribbons fit this machine perfectly, and it's a very intuitive machine to write with. The owner's manual can be downloaded for free here: https://site.xavier.edu/polt/typewriters/OlympiaSM9.pdf
If you're in the market for an extremely trustworthy workhorse that's ready to be used heavily, then this is one of the best options out there.