You can now set the following badges as your user title:
To set a badge you’ve earned as your title, go to the Badges page and select an applicable badge that you’ve earned. You’ll see a button near the top that says “you can use this badge as a title”. Click that and the rest should be self explanatory.
We will look into adding more badges and more badge titles in the future. You can follow the Title Badges page on the Wiki for the most up-to-date list.