I was thinking the Angel and Glorybringer will go on sale for sure. And... I would probably buy both.
They did just release N3 for cash, and they tend to stagger their sales.
Remember, they can't sell this stuff too often. They have to wait until people forget how much money they already spent so that they spend some more.
Another strategy is for them to let players sweat it out in Standard, dying for new cards. Then along comes the exclusive sale after several painful event runs have passed and all of a sudden they sell like hotcakes.