The help menu is a powerful tool and is great because most do not access the CLI very often. The best thing to do is make use of the help menu access and you will always be able to pick it up and get things done.
A list of namespaces to utilize to display, set and manage the ESXi host
esxcli esxcli command list
Example would be able to use the list below and pull a command like:
esxcli device alias list