Star Wars: A New Hope Bloopers & Outtakes
https://www.youtube.com/watch?v=CNfIQVplY9U&t - from the Seracco YouTube channel (17 mins long).
As far as I can tell this video contains all the officially released bloopers & outtakes + some misc. BTS material with Stuart Freeborn and the costume/MU-effect designers and some camera tests of R2-D2, Treadwell and the C-3PO suit.