Both Maya and Arnold come packaged with material presets. A great time saver!
To access to Arnold material presets:
- Click on the object
- Assign a new material (If not done so already)
- Open the Attribute editor
- Click on the material node (tab)
- In the top right of that panel click on the “*Presets” button
- A list will be displayed showing initial presets which can be modified to suit of used straight out the box