We use Artique, Bainbridge and Crescent brand acid free matboards

Solid color

There are many dozens of colors available from all 3 companies of solid color acid free mats.
Most are white core mats.  A limited number of colors come i black core and a few white and black mats come with a bright color core.

Texture paper

There are a few texture paper mats available.  Some have the appearance of flannel and some a light marble texture.

Fabric

There are a number of suede, linen,  and silk mat colors available.