The relaxation technique non-sleep deep rest (NSDR) is steadily growing in popularity. Andrew Huberman, Ph.D., a neuroscientist and professor at the Stanford School of Medicine, coined the term for this practice. Huberman has discussed NSDR widely, including on popular podcasts by Tim Ferriss and Joe Rogan. Multiple high-profile people, like Google CEO Sundar Pichai, say they practice the technique.
I like how nsdr includes the actual activation of the body instead of just focussing on mindfulness or awareness of the mind.