Pentax Spotmatics, Rolleiflex 35mm SLRs, Soviet rangefinders (and even SLRs), Prakticas, various no-name M42 & K-mount SLRs (made by Cosina, Chinon, ect..), Mamiya SLRs....

All have good sides and caveats. A lot depends on the lenses you want to use.

Personally, my Spotmatic or Soviet rangefinders are my "suicide cameras".