I've been able to feel auras since I was a teenager and trained with various energy practitioners of different styles for the last 30 years.  Though the subtle energy is often associated with religion, my course does not require or include any belief system.

Folks who I have come across who have had developed subtle energy bodies includes Reiki practitioners, Vajrayana Buddhists (Tulkus), Zen masters, The Dalai Lama, Aikido practitioners, a Catholic priest, as well as some incredibly energetic LDS members.