Design systems are important tools that facilitate velocity at scale and maintain a cohesive brand identity. They help implementors choose from a preapproved kit of parts when creating new projects. A good design system will define when, when not, why, why not, how, and how not to use a component or component group. A great system will also define code variable tokens, conversion best practices, and address accessibility. A design system should be a continuously updated project with dedicated resources.
Below are two examples of design systems that I helped implement.