VMware Cloud Director 10.x
By design, the "vApp User" role does not allow the users to see all the existing vApps but only the vApps shared and owned by the users.
To allow users with "vApp User" role to see objects of all users, the right "General - Administrator View" can be enabled on the role.
For additional information on managing global roles visit the documentation Managing Global VMware Cloud Director Tenant Roles