Pretty self explanatory, I think the transgender pride flag should be a customisation option in the flag box.
Though there is already the rainbow flag which is meant to represent the LGBTQ community as a whole, transgender people such as myself are a particularly venerable and underrepresented group at the moment. As a trans woman I am subject to frequent harassment whenever I use voice chat, not just in sea of thieves but in any online game because to some my voice doesn't sound feminine enough. This is a common issue for trans women like myself and leads to us being harassed and accused of "pretending to be a girl for attention". It is a common practise for trans women who don't feel that their voice passes to make sure that the trans flag or just the colors are visible somewhere on their stuff in games so that people have no excuse to misgender or mock their voice. This is why it is so important that there is a way that transgender people such as myself have representation, so that we can make a statement that we are here and that we are valid.
In conclusion while being such a small addition it would have a major impact for the trans player base as it would be Rare making the statement that transgender people are valid and that transphobia is not tolerated on the sea of thieves.
