Archaeopronouns

Archaeopronouns also known as Paleopronouns are any third person pronouns and forms of pronouns that were used in the languages that are no longer spoken. However, some non-binary people may reclaim them and use these pronouns to express their gender. One possible reason for using archaeopronouns is because one's language does not have gender neutral pronouns, but at one point did.

One example can be Classical Chinese pronoun "其", used by some Chinese non-binary people.

Unlike neopronouns, which are typically (intentionally) gender neutral, archaeopronouns may be gendered, though archaeopronoun users may choose to disregard the gender of these pronouns. Due to coming from extinct forms of a language, archaeopronoun might not always fit cleanly into the modern language's grammar, so alterations may be necessary.

Chinese
伊 (yī): Proposed as an exclusively female pronoun and was use from 1870-1930 before 她 became default. This usage is now considered obsolete. In some modern dialects it can be used regardless of gender.

渠 (qú): Was use since 4th to 5th century C.E., and can be used to refer to someone regardless of gender. It is preserved in some dialects as 佢.

彼 (bǐ): Was used in Classical Chinese since approximately 4th century BCE. It was used regardless of gender.

其 (qí): A possessive pronoun used in Classical literary Chinese. It was used regardless of gender. In modern Chinese it occasionally appear in idioms.

Old English
In Old English pronouns had an additional case known as the dative case, which is not used in modern English, as the accusative and dative of pronouns merged into a single case. Archaeopronoun users typically drop this form of the pronoun.

hē/hine/his/(him): Old English masculine pronouns. In this case "him" is in the dative case.

hēo/hīe/hiere: Old English feminine pronouns. In this there is no unique word for the dative case. "Hiere" was use for both the dative and genitive case.

hit/hit/his/(him): Old English neutral pronouns. In this case "him" is in the dative case.

History
The concept of archaeopronouns has existed since at least August 15, 2019, with one of the first mentions of it by Tumblr user carbonated-neon.