In response to a question about what honorifics (Sir/Madam) to use to refer to a non-binary deity, I did a little research. There’s four methods I’ve seen commonly used and two possibilities I can currently think of.
By far the most common method is to use singular they and skip any gendered honorifics. If anyone thinks singular they is a grammatical error, I invite them to read the linked wikipedia page and learn otherwise.
The second is to use “Ser” as a genderless honorific in fantasy. It has the advantage of being close enough to existing English conventions to be immediately understood. But it also has the huge detraction of being very close to “Sir”. Indeed, some writers use it as an exclusively male honorific.
The third is to use titles instead of honorifics. For example, “Captain” is gender neutral.
The last method I’ve seen is to make up your own honorifics. For example, Darth Vader. In Star Wars, Darth does not imply gender. Likewise, a Sith Lord is a title. There are female Sith Lords in the canon. If someone used Sith Lady, I’m pretty they wouldn’t live long enough to say it a second time. You will call her Lord and hope you never merit her notice. (I’m aware of the connotation of using Lord as a genderless title. I recommend not using an existing gendered title this way.)
The first possibility is switching which linguistic gender is used to refer to the deity based on context. There are historical examples of this in mythology. I strongly recommend not using this unless you’re extremely careful with it because you will be explicitly referencing existing gender roles.
The last possibility is using existing, real world genderless pronouns or honorifics. This is a great opportunity to normalize their use but it also risks confusing or tripping up the reader.