ANH
Jawa Sandcrawler.
Less vaseline under the landspeeder.
Spaceships in far distance over Mos Eisley.
The animated Dewback outside the Cantina.
Falcon leaving Mos Eisley and arriving at Yavin 4.
TESB
Wampa.
Hoth mattes.
Bespin windows.
When Luke is picked up from under Bespin Cloud City, when the Falcon's hatch opened, light was pouring in when viewed from inside, yet pouring out when viewed from outside (always bothered me), extra hatch added to explain this.
ROTJ
Nothing.