These are some of the materials i created in octane (c4d) as a practice about 15 material you can download the pack from down below, I have also added materials like dirt and rust which you can use them to create different materials by mixing them .

S p e c i a l   t h a n k s   t o
 
Quixel team for their amazing shader ball that i used 
Grant Warwick for his shader ball which is included in the c4d scene 
i have also included the corona shader ball from corona-materials.de 
i also included a modified quixel shader ball with octane logo on it if you want to use it 
also big thanks to www.threedscans.com for the awesome dog scan that i used as a testing object 
www.texturelib.com for their textures 
www.hdrlabs.com for their HDRI

Have Fun learning and creating materials .
Painted Metal with blood stains
Brass
chameleon paint 
metal
Rusted Metal
Tank material
Simple Gold
Copper
Worn Painted metal
Coal Dirty Wood 
Normal Wood
Plywood
Rough wood
Red Wood
Mossy Rock Surface
Amber
this is a test using the scanned Object i mixed the dirt material with the rusted metal which they are both included and this is the result , you can play around with them or dissect them to learn new things especially for beginners have fun .
This is the perfect layout that i used to create these materials, you can replicate it in c4d 
PS: if octane crashes on you when you try to render your own geometry remove the included softbox lights group and save and re render and everything should be fine