Jelly, 8 bytes
Really, 8 bytes? Please, tell me I missed something!
32r126Ọḟ How?
32r126Ọḟ - Main link: list of characters s 32r126 - inclusive range from 32 to 126 = [32,33,...,125,126] Ọ - cast ordinals to characters = list of printable characters ḟ - filter discard if in s Alternatively
“ ~‘r/Ọḟ - Main link “ ~‘ - code-page indexes = [32,126] r/ - reduce by inclusive range = [32,33,...,125,126] Ọ - cast from ordinals to characters = list of printable characters ḟ - filter discard if in s Since this challenge a new atom which yields all printable ASCII characters, ØṖ, has been introduced making the following work for 3 bytes:
ØṖḟ