Layer Materials question

How can I efficiently manage my material drop-down window in complex scenes to prevent it from getting bogged down when I import new assets that bring other materials with them? Can the material drop-down window be purged in Rhino 7 in any way to improve productivity? I’ve added a screenshot to show what i mean. This is a blank canvas, I thought i had saved only the geometry. yet in brought all these material and material copies with it.

Thanks in advanced.

command:

-purge

materials=yes

will get rid of unused materials

in the material tab, you can also find an option to only display used/unused materials

another somewhat related option is to create material “tags” and display only materials that you filter via searching for these “tags”

https://docs.mcneel.com/rhino/7/help/en-us/index.htm#user_interface/rendercontenttags.htm?Highlight=material%20tag