Dynamics CRM 2016 or later allows configurators to build segmented solutions that only include the fields, views, and entity components necessary, rather than adding the entire entity to the solution.

Be aware that if you add a lookup field to your solution that references an entity that is not already part of the solution, Dynamics will automatically add the entire lookup entity to the solution. This will make your solution not so skinny.

The recommended best practice to avoid this from happening is to first add the lookup entity to your solution, without all of its baggage, then create your lookup field.