Logged in tonight in order to check on something and was pleasantly surprised to see an
announcement that Icelandair was back as a Mileage Plan Partner--complete with access to the Saga Lounge for Gold and Gold 75Ks--with "more elite benefits to come in 2016."
There's also a Double Miles offer for Icelandair Flights between October 1 and December 15.
Quite pleased. Nice to see them back!