Here's an idea for two keys:
A 'grue' key: Just a black key, doubleshot, with two eyes and perhaps a bit of a smile. You should all know what a
grue is, if not, for shame.
And, of course, a 'Z' for 'Zork':
UV printing for the stone-masonry 'Z' or maybe use the more simple, but more stylized 'Z'?