Pronouns

In English all third person personal pronouns have five grammatical form. The forms are:

Nominative: Used when the pronoun is the subject of the sentence. (They went to the store.)Accusative: Used when the pronoun is the object of the sentence. (I met them today.)Pronominal Possessive: Used to show possession/relation to a noun, coming directly before the noun in question. (They walked their dog today.)Predicative Possessive: Used to show possession of a noun, coming directly after a linking verb. This is the least common pronoun form, as it requires a very specific sentence construction that is not common in normal speech. When listing out the forms of a pronoun, this is the form that it most commonly left out. (If I need a phone my friend will let me borrow theirs).Reflexive: Used when the subject and the direct object in a sentence are the same. In English these pronouns always end with -self (singular) or -selves (plural). (They have to drive themself to school.)
In some pronoun sets two or more of these forms are the same. For example, in the he/him pronoun set the pronominal possessive and the predicative possessive forms are the same (his). In the she/her pronoun set the accusative and the pronominal possessive forms are the same (her). In the they/them set all five forms are different.

source: Pronouns | LGBTA Wiki

For more information:

• Neopronouns
• Pronouns
• Neopronouns
• Neopronoun List
• Neopronoun Masterlist