Polyanthropy

Polyanthropy is a term with two definitions. It could either be a gender neutral version of polygyny and polyandry (example: a person who marries multiple men and women) or it could be an umbrella term for polygamy and polyamory.

The adjective, referring to the person or qualities, can be polyanthropist, polyanthrope, polyanthropic, polyanthropical, polyanthric or polyanthropous.

Flag
The flag was coined by Tumblr user beyond-mogai-pride-flags on September 16th of 2018.

Etymology
Poly- comes from Greek polus ‘much’, polloi ‘many’. -anthropy from Ancient Greek ánthrōpos “human”.

Resources
https://beyond-mogai-pride-flags.tumblr.com/post/178157854100/polyanthropic-pride-flag