I know of someone broadening the traditional "Mr/Mrs/Ms" "M/F" and is unclear on what to broaden it to, nor can find agreement amongst the clients as to what to broaden it to, beyond that they want it broadened.
The former is officially used in GB, but it sees informal use in US media and elsewhere. I live in a country that doesn't use honorifics, but I use 'Mx' where it's required. I'm unsure about non-English equivalents for 'Mx'.
The latter sees use in BE, DE, IS, MT, NL and on job boards in Europe and more progressive areas. It's also seeing use in the US on passports and NY birth certificates.
There are of course others, but none as widely adopted as these.