Crosspronominal

Crosspronominal, also known as transpronominal or alterpronominal, is the phenomenon of using atypical pronoun sets—pronouns that do not align with or are uncommon for one's gender identity. It is a form of gender non-conformity and falls under the umbrella of pronoun non-conforming. Examples include binary women using any pronoun(s) other than she, binary men using any pronoun(s) other than he, and non-binary people using she or he. Non-binary people who use he/him or she/her may also identify as difpronominal.

History
It is unknown when the term was coined, however it has been used amongst the community since 2018.

Flag
The flag was coined by Tumblr user beyond-mogai-pride-flags on January 28th of 2019. It uses colors similar to the transgender flag, but has no confirmed meaning.

Resources
https://beyond-mogai-pride-flags.tumblr.com/post/182373614140/crosspronomial-pride-flag