Are there any? I've started to update to 8.1 installation now that you can get the W8 OEM key from the BIOS with a handy tool. However, when testing the image I've made, the old W8 keys I had do not work anymore.

 

Again this is not for activation only temporary/trial install. Core and Pro since that's what customers at work use.

Edited January 2, 201510 yr by Nessaja

http://technet.microsoft.com/de-de/library/jj612867.aspx

other keys are not available

Edited January 3, 201510 yr by gorgone

Here's the English link - http://technet.microsoft.com/en-us/library/jj612867.aspx.  As gorgone said, please note that these are volume licensing edition keys. As stated at the link -

 

If you want to…
Activate Windows outside of a volume-activation scenario (that is, you’re trying to activate a retail version of Windows), these keys will not work.

 
Cheers and Regards