HP drivers
From WPKG | Open Source Software Deployment and Distribution
Most HP drivers (audio, graphics, keyboard, network, input devices etc.) come as InstallShield packages. The installer usually have name like sp<number>.exe, for example, sp32556.exe is the name for Broadcom network drivers.
Sometimes, it will install silently with a /s switch, i.e.:
sp32566.exe /s
Unfortunately, in most cases manual intervention is needed (i.e., using other InstallShield switches, recording the installation etc.), so there is no golden rule here.
Sometimes, after starting the installer, you will find an extracted MSI package in %TEMP%.