what about mix? (I think that was the other one?)
To my knowledge, Mix isn’t used as a pronoun, but as a title.
A title is what you stick before the name if you’re being polite, like Mr. John Smith, Miss. Jane Doe, Mx. Alex Green.
A pronoun is like she, he, it, them, they, hers, his, their, etc. The photoset showed examples of gender-neutral titles, as they have different forms and it’s often hard to figure out the correct way to use them.