This section of the reference discusses extension commands in the extension DLLs that are used less often.
These include:
Logger Extensions (Logexts.dll)
NDIS Extensions (Ndiskd.dll)
RPC Extensions (Rpcexts.dll)
ACPI Extensions (Acpikd.dll and Kdexts.dll)
Graphics Driver Extensions (Gdikdx.dll)
Kernel Streaming Extensions (Ks.dll)
SCSI Miniport Extensions (SCSIkd.dll and Minipkd.dll)
Kernel-Mode Driver Framework Extensions (Wdfkd.dll)
User-Mode Driver Framework Extensions (Wudfext.dll)
WMI Tracing Extensions (Wmitrace.dll)
OEM Support Extensions (Kdex2x86.dll)