"A Texture Library (121 Ground Textures)" is a creation of William White . Vol.2 includes 63 HQ Textures (2592 X 2592 pixels) of ground along with their Normal, Height and Specular maps.
All textures are seamless and their maps are in black and white letting you make changes like switching a height map to normal map.
The package also includes ready made HDR materials for every texture.
(Steep parallax shader is NOT compatible with Unity5)