The "CD" might be referring to the CDTV, I'm not sure. It was essentially a fancy multimedia device though. The CD32 was the one specifically designed for gaming. You should be able to tell what they're for just by looking at file names though, based on the games.
In any case, C64, Vic-20, Plus 4, and CD32 (and CDTV for that matter, although I'm not sure why you'd want that) are all separate things.