As an aesthetic ending in -core, it opens itself up to coric genders based on the aesthetic. The billwurtzcoric pride flag, coined by genderqueer-dream on Tumblr in April of 2020:
Some otherkin individuals have also latched onto the concept of billwurtzcore as a kintype! The billwurtzcore kin flags, made by kinnie-thots-flags on Tumblr: