Sisal, Seagrass, Jute and Coir. All these products can make a beautiful flooring option. Seagrass is as it sounds, a grass harvested from the sea. Sisal and Jute are from plants.
Jute is the least durable of these types of flooring as it is the softest, maybe think about using it as a rug in a bedroom.
Sisal is very popular and takes to dying very well, so the colours remain stronger for longer.
Coir is the most durable floor covering, made from coconut husks, but rough underfoot and usually used in doorways and boot rooms as mats.
Seagrass is usually the least expensive of the natural floorings; it does not hold colour so well is more useful in areas out of the light and sun.