One of the first examples of gender neutral pronouns is from Charles Crozat Converse, who presented the Idea of the pronoun "Thon," short for "that one." This pronoun was added into the dictionary in the 1930s, but is known to be used since the 1850s. 

What is commonly known as "Spivak pronouns," includes pronouns popularized by James Rogers (E/em/es), David Lindsay (ae/aer/aers), Christine M. Elverson (ey,em,eir),  Lillian Carlton and  Donald MacKay (ee/ees/eeself), and Michael Spivak and Roger Crew (E/Em/Eir)

James Rogers first used E/em/es in an 1890 editorial as an acknowledgement of Charles Crozat Converse's "thon."

David Lindsay used the pronouns ae/aer, now known as Lindsay pronouns, in the 1920 novel, A Voyage to Arcturus. 

The Chicago Association of Business Communicators awarded Christine M. Elverson for finding the gender neutral pronouns ey/em/eir, which is a modified version of they/them/their pronouns without the "th." Elverson made these "transgender pronouns"  to make a sentence smoother, without having to write "he/she" or getting confused by using "they" too many times in a sentence. 

linguist and poet Lillian Carlton reported the newfound pronouns of "an American professor," believed to be Dr. Donald MacKay. The pronouns known as epicene, or bisexual Pronouns (ee/ees/eeself), were thought to be too complicated and confusing by Carlton. In modern times, kids are taught about "kind Ed," or the "silent E," which "makes the vowel say its name." Though epicene pronouns have mostly been ignored because of the way the "silent E" impacts the English language, they are still rarely used. 

Michael Spivak created the pronouns E/Em/Eir to refer to a person using gender neutral pronouns in his 1983 book, The Joy of TEX: A Gourmet Guide to Typesetting with the AMS-TEX Macro Package. In 1991, a LambdaMOO programmer included E/Em/Eir pronouns under the gender "Spivak," giving the option for players to be referred to in said pronouns.