Which term best describes the guidelines, protocols and rules of conduct that design teams develop?

The guidelines, protocols and rules of conduct that design teams develop are called Group norms

They are often unwritten and informal rules that govern the conduct of individual in the group. Group norms vary based on the group and issues important to the group. Without group norms, individuals would have no understanding of how conduct themselves

I believe the answer is: group norms

unlike the law that regulates criminal activities, group norms tend to not formaly written and wouldn't have specific punishment for each violations.

But, it is generally known by all people from a certain culture and would be expected to be followed both by members or guests that come into their territory.