Windows Server 2016 Standard License for use on a single server and 1 additional Hyper-V instance on the same server. If the host is solely used for virtual machines up to 2 Hyper-V instances can be deployed.
Windows Server 2016 Datacenter License for use on a single server and unlimited Hyper-V instance on the same server.
Remote Desktop Service CALs grant access to your user/device to remote into the server
Required for every user or device remoting into your Windows Server.