Natural fibres such as cotton, bamboo, and hemp are used to make these fabrics. Because they're comprised of natural fibres, these fabrics will biodegrade organically if they're thrown away.
Furthermore, these fabrics are usually dyed with non-toxic, eco-friendly dyes. These materials reduce the use of synthetic fabrics, Blackbird Fabrics and Nature's Fabrics are two places where we get natural fibre fabrics.