Peach skin is a standard material commonly use for dakimakura. It is a material that is a great "all rounder" in terms of elasticity, softness, and print quality.
2wt has the best elasticity, softness, and print quality. They also last the longest.
We only want to offer you the best two available because we believe that is all you really need and there is less hassle in deciding.
Materials such as velvet and Japanese textile are much lower grade and print quality, so we do not wish to risk offering you a bad product from those materials.