@FireaLoup You can use "es", but it's very uncommon, and it has a certain dehumanizing touch to it. The neutral grammatical gender is also called "sächlich" in German, which could be translated to "thing-ish". But some people prefer the "es" pronoun anyway.

There are other pronouns as well, which were created in recent history. For example, "ersie" or "er*sie", or completely new words like "xier" or "nin". There's a list in the Nichtbinär Wikia: http://de.nichtbinaer.wikia.com/wiki/Pronomen