How to get the available Azure VM sizes for the availability set using PowerShell?

To get the Azure VM sizes available for the availability set, we can use the Get-AzVMSize command with the availability set name. Before running this command make sure that you are connected to the Azure Cloud (if not use Connect-AzAccount) and proper azure subscription (Set-AzContext to set the Azure subscription)

Get-AzVMSize `
   -AvailabilitySetName myAvailabilitySet

Here the Resource Group name is MyResourceGroupAvailability and the Availability set name is MyAvailabiltyset.