The best fabric for comfortable nightwear depends heavily on individual sensory preferences and thermal needs, but natural fibers like 100% long-staple cotton, organic bamboo viscose, modal, and silk are universally praised as top-tier choices. Cotton and bamboo offer exceptional breathability and moisture-wicking properties that prevent overheating, modal provides a silky-soft drape with high durability, and silk delivers luxurious temperature-regulating properties that keep the skin cool during hot summer months and cozy during winter.