Although it's better I find to use actual photos as a base for creating materials in Substance, I love to just jump in and whip up something I need if I don't have it. It's not always easy to do that, but there are multiple ways to achieve what you are looking for.
A nice wall or ceiling material, with scrapes of drywall compound and spatters of paint:
Wood paneling w/o knots:
Wooden rooftop shingles with parallax occlusion:
Cracked rock surface with water gathered in its crevasses: