All the information you need to be recognised outside of the gender binary
Misc, or Mx: A Gender-neutral Title
Unless you’re a qualified doctor or a professional religious person, your title options are far from non-binary. Ms and Mr add a formality buffer that many companies and organisations like to use, as it makes almost everyone feel more comfortable. The trouble is, when someone is asking us for a title, they’re basically asking if we’re a guy or a girl. The answer is almost always neither.
There aren’t many out genderqueer folk around, but those of us that are working towards recognition and acceptance are generally using one of two titles. (Correct me if I’m wrong, so I can add the others here too.) These titles are also useful to use when you need to address someone formally, but are unsure of their gender. For example, someone has written to you and addressed you as Mr or Ms Surname, but they’ve signed the letter “Sam Smith”. As Sam could be either male or female, or genderqueer, Misc (Sam) Smith is an appropriate response, until Sam corrects you.
Here’s a list and here’s a discussion in the comments about businesses and organisations that are happy to use Mx or Misc. Edit: And here’s a regularly-updated wiki page UK Recognition on the nonbinary.org wiki, and here’s a downloadable PDF of evidence to show to organisations who think it’s not a “proper” title.
Mx (eg: Mx Sam Smith, Mx Smith)
Pronounced Mix. From what I can tell, this one has been around longer. The x acts as a wild card, taking the usual title format of Mr and Ms and putting in an x to remove the gender in the title. (If anyone has a source for this, I’d love to link to it.)
Misc (eg: Misc Sam Smith, Misc Smith)
Pronounced Misk. The roots are interesting. The word miscellaneous comes from the Latin miscellus, meaning “mixed.” I think a lot of genderqueer people would say that they have aspects of various genders at various times. These days, it’s often used to categorise something that doesn’t have another previously defined category. (First page.)