Some examples: VM Ware VM:

VMware-56 4d ec 19 35 ac 31 08-ed d8 4d 29 b4 d7 b8 8e

Virtual Box VM:

NO SERIAL

AWS EC2:

ec21024d-b407-f4d9-995a-23b48ac03cc2

Google Cloud VM:

GoogleCloud-ED2B6257H2B220DD5698EC293C0