VMware Cloud Director 10.6.1
VMs that are created as standalone VMs do not have vApp objects associated to them in the user interface. This is expected behavior.
If a vApp is desired for the VM, then follow the process outlined here to Convert Your Standalone VMware Cloud Director VM Into a vApp.
Standalone VMs do have hidden vApp container objects associated in the back-end. These can be viewed over the API by performing a GET request to the VM and examining the API response:
Example:
GET https://cloud.example.com/api/vApp/vm-#########-####-####-####-########
Within the response body locate the vApp ID which has the following format:
Example:
href="https://cloud.example.com/api/vApp/vapp-########-####-####-####-########" type="application/vnd.vmware.vcloud.vApp+xml"
If you then perform a GET request against that vApp ID, the response body of the vApp contains API element <autoNature>true</autoNature> which indicates this is a hidden vApp object.
Example:
GET https://cloud.example.com/api/vApp/vapp-########-####-####-####-########