While Gore-tex is to shell layers as Kleenex is to tissues, there are a number of waterproofing materials that rain jackets for hiking use to keep you dry, with names like Shakedry, Omni-Dry, and HyVent. Many of these are proprietary to a particular brand. While in the past many rain jackets for hiking relied on PFAS (think teflon) to provide lightweight waterproofness, there is a shift away from these chemicals as people learn more about the damage they do to human health and the environment.