This is just a quick one, if you have dell machines (not sure if other manufacturers do it) but one of the BIOS options is ASSET TAG. Now this does not, as you would expect, appear in Win32_BIOS, instead it appears under Win32_SystemEnclosure.
So with that here is a simple report query to get a list of all systems, their serial numbers and asset tags.
netbios_name0 AS Hostname,
vgspcb.SerialNumber0 AS [Serial Number],
SMBIOSAssetTag0 AS [Asset Tag]
INNER JOIN v_GS_SYSTEM_ENCLOSURE vgssyse
ON vrsys.ResourceID = vgssyse.ResourceID
INNER JOIN v_GS_PC_BIOS vgspcb
ON vrsys.ResourceID = vgspcb.ResourceID
ORDER BY netbios_name0