Ecolect is a great site for green materials. They have initiated a service called Greenbox, which is great too! You sign up (pay $849.95) and every 3 months, you get a collection of 8-12 cutting-edge materials, shipped direct to you. Innovative and environmentally friendly material – ideal for design, engineering, and marketing teams. The samples will highlight trends that other material producers are setting, and serve as inspirational and informational reference for people working with product development.