File:Bigender by Milith Rusignuolo.png

Summary
From https://web.archive.org/web/20180210192310/https://avia-viridis.neocities.org/flags.html

"Since the flag at the time being used for bigender people was originally the intersex flag, I wanted to try making my own, which I posted shortly after the androgyne flag, on 13 July 2015. I tried to use secondary colours, which represent a blend between two colours. The plus sign comes from the stylised spelling of the word as bi+gender, as well as representing putting two things together. The yellow, white, and blue were added for aesthetic reasons. I have to say, I still love the concept of this design, and I really do wish that it could have caught on (with some tweaks, of course). But it's a fruitless endeavor to promote it, given that there are so many bigender pride flag designs."