The reusability of modular, embeddable components is a key determinant for the success of modern programming languages to ensure efficient and high-quality development. However, there is a gap in the field of domain-specific modeling regarding reusable components at the model level. While libraries are relatively common and a de facto standard for prominent programming languages, establishing model libraries is still in its infancy. This paper specifies building a model-driven component library that utilizes a self-extension mechanism. We demonstrate an approach to structure, build, and integrate such a library using a wide range of GUI components, from essential atomic elements and more complex composed components to specifically tailored ones for particular application domains. Employing such libraries at the model level further supports the goal of model-driven engineering to assist domain experts in efficiently building high-quality systems.