The short-lived Republic of Deseret, and its second incarnation as the State of Deseret (which kept existing for somewhat longer as an underground shadow government for Utah Territory), remains quite attractive for alternate historians. After all, it represents perhaps the only attempt to create a theocracy in North America, and the only time the United States Army suppressed a religious insurrection on American soil. While the Mormon War may appear a minor issue today, it was major enough at the time that the first Republican platform in 1856 excoriated “those twin relics of barbarism — Polygamy, and Slavery.”
A surviving Deseret is frequently combined with a Confederate victory timeline - in part a recognition that it requires a less-powerful US, in part following in the tradition of works such as Bring the Jubilee and TL-191. This idea remains a popular subject for discussion.