You might want to look especially at C0 and C1 control character http://en.wikipedia.org/wiki/C0_and_C1_control_codes
The wiki says, the C0 control character is in the range U+0000—U+001F and U+007F (which is the same range as ASCII) and C1 control character is in the range U+0080—U+009F
other than C-control character, Unicode also has hundreds of formatting control characters, e.g. zero-width non-joiner, which makes character spacing closer, or bidirectional text control. This formatting control characters are rather scattered.
More importantly, what are you doing that requires you to know Unicode’s non-printable characters? More likely than not, whatever you’re trying to do is the wrong approach to solve your problem.