Theo

Theo is also used as a feminine given name, as a short form of Theodora. However, it's more common for males. So, I think that the "Gender" of this name should be updated from "Masculine" to "Masculine & Feminine".

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Source: https://en.m.wikipedia.org/wiki/Unisex_name

Also Swedish, Danish and Norwegian: https://www.nordicnames.de/wiki/Theo

This could be a short form of the name Matthew because of how many Matthews there are.

This is currently a very popular name for nonbinary/genderqueer young folks, so it should probably be listed as unisex as well.

Also Estonian: https://www.stat.ee/public/apps/nimed/

I'm a girl and my name is Theo! (My real name is Theodosia but it's kinda old and I never use it anyway.)

Theo is currently 22nd place in Germany (2016). (source: http://www.firstnamesgermany.com/).

Also used in Greek as short form of Theodoros/Theofanis/Theofilos/Theofylaktos or any other name that begins with the Ancient Greek element "theos", means "God".