I am unsure why you cannot get these any more from Dell’s website. They used to be here: https://www.dell.com/en-us/blog/free-idrac-enterprise-extended-trial-license-from-dell-emc/
They are for all idrac 7, 8, and 9 licenses to upgrade you from express to enterprise. At least they’ll work for 240 days, caveat for idrac7 being 30 days. So they are useful in a pinch, or if you are waiting for a procured license to come through. I applied one to an idrac8 server recently and it still worked, so I do not think they are expired. Here are the links, self hosted on vivithemage.com. Right click and “save as”.
iDrac 7 (30 days) :
https://vivithemage.com/extra/Dell_Drac_Temporary_License/iDRAC7_Enterprise_30 day Trial license.xml
iDrac 8 (240 days) :
iDrac 9 (240 days) :
iDrac 9 (240 days) : This one is specific to the Rxx15 series servers.