In many languages, words called pronouns are used to refer to people in place of their names. Said words include but are not limited to; I, we, us, me, she, he, and they.
In the English-speaking world, it is most common that women will be referred to using the pronouns she/her/hers, while men while use he/him/his. However, this is not the case for everyone. Many non-binary people will use the pronouns they/them/theirs.
Pronouns are not so strict, despite what some may lead you to believe. Many people will use more than one set of pronouns, and some will use neopronouns such as it/its or xe/xem/xyrs. Due to the diversity of language, some people will come up with their own pronouns to use.
Some people will try to argue that neopronouns are a new phenomenon. While it is true that neopronouns have become more common in recent years, there is no denying that people such as writers and activists have been coming up with gender-neutral pronouns for centuries.
Nounself pronouns are a form of neopronouns. Nounself pronouns are created by substituting various nouns in place of pronouns. Some examples include doll/dolls/dollself and star/stars/starself. Nounself pronouns are particularly common among neurodivergent non-binary individuals who use xenogenders. The reason being is that for some people, using descriptors of objects are easier to use to describe their gender than the traditional "masculine" and "feminine" identities.
In a similar line of thinking as nounself pronouns, some people will use emoji pronouns. Examples include 🦑/🦑self and 🌿/🌿self. Emoji pronouns are not usually intended to be spoken out loud, and are instead used as a way to express one's identity online. They are also sometimes used by younger trans people in an effort to try and stay closeted if they live in an unsafe household where transphobic family members may try and peek at their messages.
LGBTQIA Fandom - Neopronouns
Mermaids UK - Neopronouns
Merriam-Wester Dictionary - Pronoun
Merriam-Webster Dictionary - They
Merriam-Webster Dictionary - Thon
Pronoun Dressing Room
pronoun page
them - Gender-Neutral Pronouns 101: Everything You've Always Wanted to Know
well and good - Neopronouns Are a Form of Gender-Neutral Pronouns, and Understanding How To Use Them Is Key To Allyship
Wikipedia - Neopronoun