There's no real theory or practice to speak of, just an infrequently updated zine and a tabletop rpg. While the most fervent supporters of anarcho-transhumanism as a concept are all adjacent to Center for a Stateless Society, you'll be hard-pressed to find any left wing market anarchist actually make that connection. The term hasn't moved past the speech William Gillis gave five years ago. Because of this, those who are interested usually end up reading Bookchin and go through a "Solarpunk" phase before moving on with their lives by actually reading Marx.