This was cool, thanks! I followed the exercised and made my first three materials with shader graph, they are on the spheres in the scene. 

For the other still life materials, I experimented with existing maps from the project (mainly the tiled ones) to create new materials with more texture for the fruits. A light map ended up on the table which worked surprisingly well. I added detail to the fruits by adding existing height maps (concrete, pavement... with changed values in size and offset) to the base map image slots and I used a colourful noise texture on detail maps to create subtle colour variations in the fruits.