I would think you would want to include
acs_object_types, acs_attributes, acs_privileges, acs_rels
(and maybe the associated group tables like membership_rels etc), site_nodes, and maybe some of the apm tables
within a diagram of the core datamodel.
In CR, cr_child_rels is important (and a lot of the other
tables like cr_folders and cr_templates are worth covering).
