Have a look at albedos, normalmaps and heightmaps. I normally use different parts of different textures to make something new like using the mortar normal map on the dirt albedo to make it look rough even though they aren't from the same group.
Example spheres are made in unity.
Galvanised
Diamond plate
Flemish bond
Brown
Natural white
Black
Gritty squares
Dirt
Green plant
Leaves (transparent)
Orange plant
Purple plant