Most of the Dynamics 365 extensions are built in a way to promote reusability.

Dynamics 365 common solutions can bundle reusable configuration and customization (schema, client-side, or server-side extensions) across different instances. Building reusable solutions is described in Chapter 8, DevOps. Furthermore, the Dynamics marketplace AppSource has hundreds of reusable Dynamics 365 solutions that can be installed on your online instance to enrich your platform's capability.