I don't think there is key for Skype for Business 2019. When, I installed Skype for Business 2015 there was no key required during the install. I even installed Skype for Business 2019 preview and was not prompted for any key during the install.
OK, my bad: There won't be a different OOS for 2019. You'll continue using OOS, just updating it as necessary.
I can confirm the one for "Standard" matches what's shown in my company's VL portal. I haven't yet installed or tested it yet though.
Thanks, I have not tried yet. I took the thing from an Iranian site. Has the same keys. I hope it works. What worries me, if someone knows, is that minimum of 128 Gygabytes of RAM. Is that a real fact or an exaggeration ?
now there is Office Online Server 2019. https://forums.mydigitallife.net/threads/solved-office-online-server.74102/page-2#post-1487488