I've read the whole DMTF - SMBIOS Standard Specification but I can't find the HARD DISK and Ethernet PCI Card Type structure using SMBIOS Firmware Tables.
Do you know which Type refers to hard disk and ethernet card, if for example I want to read the Serial Number of the hard disk and MAC?
As you have discovered, this information is not part of the SMBIOS specification.
I'm not sure of your application, but this information is accessible via WMI (Windows Management Instrumentation), assuming you're running Windows. E.g.:
ROOT\CIMV2:Win32_DiskDrive.SerialNumber ROOT\CIMV2:Win32_NetworkAdapter.MACAddress