There's also Luke's new blue lightsaber from the ROTJ trailer:

The idea from ANH was that blue sabers = good guy, red sabers = bad guy. End of story, no other colors. But then Luke's blue lightsaber was almost invisible against the desert dunes in the sail barge scene, so the blade color had to be changed during post-production.

This change allowed Lucas to get away with deleting Luke's original introduction scene, in which we see Luke finishing construction of his new lightsaber. The green-colored blade revealed during the sail barge battle is instantly obvious as a newly built saber, in a way that a second blue lightsaber would not be.