Mr. Mime: Despite the name, may be of either gender. Additionally, Mr. Mime’s color scheme matches the colors of the trans flag.
Azurill: Female Azurill have a 25% chance to evolve into a male Marill.
Gardevoir: From tomboy to fabulous person in a long dress, Gardevoir may be either male or female.
Sylveon: Colors of the trans flag, and flag like appendages possessing said colors - interesting choice, as eeveelutions usually represent the main characteristic of its type.
Mimikkyu: Hides their true self in an attempt to be more socially accepted. Hopefully will get an evolution where they finally accept themselves.