In general there are a few rules when it comes to pot colour selection that are based around aesthetics in order that your bonsai trees are displayed to their advantage.
Selection tips
Guide on Choosing the Right Bonsai Pots - Hooked on Bonsai
The Art of Bonsai Pot Selection: Enhancing Your Bonsai's Beauty - Bonsai Plaza
From clay to Bonsai Pot - Bonsai Empire
How to start winter bonsai in Japan - Japan Today
Selecting a suitable container - Bonsai Tree (Pty) Ltd.
Gorgeous Bonsai with Very Attractive Pot in Green Color -Excellent Gift.. buy online plants and trees at pixies Gardens.
16 Common Bonsai Tree Species to Grow
Kid's play or pot? – Bonsai Today
Japanese bonsai tree in red terracotta pot, In a colour palette with complimentary red and green toned colour swatches Stock Photo - Alamy
Bonsai pot colour guide
Bonsai pots - why they are integral to bonsai aesthetic and health