Natural fibres are biodegradable and renewable with an unquestionably retro cool. And there's a reassurance to using materials that have been tried and tested for generations.
Cotton canvas makes a great material for tents, eliminating condensation and insulating in the heat or cold. Plus it's highly UV resistant, lasting for years. Cotton is also really hardwearing and a waxed finish makes it a great material for packs and bike luggage.