To help people get familiar with Bella, we have uploaded several sample scenes, for use with Bella GUI, and in some cases, Maya: https://bellarender.com/scenes. So far, these are the scenes:
Core materials
Smart materials
Ceramic material
Plastic material
Metal material
Urethane material
Derby-car scene
Wheel scene
Candy-coat scene
Material preview scene
If you have requests for specific types of scenes, please feel free to let us know in this thread. 🙂