A non-exhaustive list of lgbtqA composers/arrangers who have written choral music
If you know more I'd love to keep this list growing!
Historical: Barber, Britten, Copland, Menotti, Bernstein
Paul Caldwell (of Caldwell & Ivory)
Mari Esabel Valverde
This page features various scholars working on gender-sexual diversity issues in choral music education.