I am new to Azure management libraries for .net. How can we enumerate VM instance sizes available with respect to subscription or in general using Azure Management libraries for .Net or Rest APIs? Please suggest.
You can get a list of VM sizes for a region by calling
https://management.azure.com/subscriptions/{subscription-id}/providers/Microsoft.Compute/locations/{location}/vmSizes?api-version={api-version}
As documented here - List all available virtual machine sizes in a region
There is also a .Net Class for the same, but I've not found any examples of it being used - documented here - VirtualMachineSizeOperationsExtensions.List