Just discovered folks in the org have figured out they can edit their front facing name to include ASCII characters that show as emojis. What's irritating me is that I can't figure out a way to SOQL all user records to find WHERE any given character in a name != [a-z] OR != [A-Z] OR != [0-9]. Basically what you would do with a Regex, if SOQL let you do a Regex.

Any ideas? I want to make it as dynamic as possible rather than just having a list of every possible ASCII character they shouldn't be using.