Texture is often completely ignored when it comes to selecting a rug.
This is completely misguided (and such a shame!) as there is a myriad of complex structures available beyond the classic wool pile structures that populate our environments. A room with a combination of textures can feel rich, sophisticated and accomplished. Often the starting point can be found in existing soft furnishings or furniture, which should help inform and guide you.
Soft sumptuous upholstery fabrics like velvets or chenilles can look amazing when contrasted against a hard smooth surface like sisal. A leather sofa can look great against something with a rich, deep, soft pile.