Ambi Bi is combination term for those who are Ambiamorous and under the Bi-umbrella. It symbolizes a willingness to love more than one person and more than one gender, but not necessarily a preference between loving one or loving more, just the possibility for it.
History
Ambi Bi was coined by Starstruck4Light#8094 on Discord.
Flag
The Ambi Bi flag was created by Cinnamon's Law#5621 on Discord. It is a combination of the bisexual and ambiamorous flag.
References
Screenshots of the flag and term's coining discussion :