the metal cards with pre-production art, do not know what company put them out.
His website sells an exclusive dvd, and has most of his stuff up.
Of course their are the three original art of star wars books,
plus the three sketchbooks, and the 3 portfolios put out by dell rey which are now collector's items.
There are also three slideshows of his preproduction artwork on the definitive edition laserdisc from 1993.
there is some material on the bonus disk from the new official dvd release, like the trailer for empire which uses only mcquarrie artwork with narration. Plus his art for the unreleased poster for the star wars, it is in a book i have called from star wars to indiana jones. His art for the 1976 pre release paperback for star wars, and for splinter of the mind's eye. and there also are illustrated editions of the novelizations of empire and jedi, with sketches and the empire strikes back notebook.
the art of star wars universe co-written by kevin j. anderson has some other stuff. one sketch is in star wars the magic of myth by mary henderson. their is also the new cinema of george lucas book, quite expensive, and the star wars chronicles also quite expensive. a wealth of materials exists in the lucasfilm archives, that has never been seen or released and probalbly never will. Just like we will never get to see the rough cut of a new hope, or read all the screenplays/ story treatments that are all locked away by lucas. this is including the so called non existing original cuts of the films, and the treatments for episodes 7-9 which has been verified to exist but he insists that they don't, oh yeah and those so called original treatments for episodes 1-3 which are buried because he never had them, yeah right.