ProtonVPN is nice and free
Have not integrated into Win10PESE yet, maybe it will be easier in Win7PE for you.
You will definately need network drivers, I recommend..
Lan: Dlink,Jmicron,nVidia,VIA, asix, bigfoot, etc
Wlan: SIS, VIA, netauthurx, etc
Along with recent realtek, aethros and drivers as well as drivers for USB dongles etc.
It will be difficult to predict everything you will need without testing, you should ask your users for feedback regarding drivers after your initial release or add something to your build that makes feedback easy for the user to accelerate the process...
