As described in Creating early bound entity classes, CrmSvcUtil is a great utility to generate early bound entities that improve your development productivity.
CrmSvcUtil, as it is, generates all entities associated with a Dynamics 365 instance. The generated file is usually quite large and onerous to inspect. In this recipe, we will write a small extension to only generate early bound classes for custom entities that have a prefix of our choice, in this example, the packt_ prefix (our Dynamics 365 publisher prefix).