Lord [name], my [name], my dear [name], the one they call [name], oh great and powerful [name].
Jokes aside, one I've heard of that I liked was "misc" like miscellaneous lol. That one works a bit better in writing that verbal though.
Some other popular ones include Mx, M, Ind/Div, N/A, Mt, Nb, and many others.
For my own personal suggestion, I kinda like the idea of using "The" as a gender neutral title. Like instead of Mr or Ms Smith, it's The Smith. Has a nice ring to it lol