This video covers the very basics of materials: how we describe physical objects in the real world, and how we map these to the "channels" of a material. It talks about:
Color / Diffuse / Albedo
Roughness / Bump / Normal
Specular / Shininess / Smoothness / Metallicity
Reflectivity
Opacity / Transparency / Alpha
The Fresnel Effect
Self-Illuminating Materials
Unlit Materials
and more