Great idea, Thrawn!
A section of Innoventions still has the carpet with the old Communicore logo on it. It's the area that's often used for various "festival centers," behind the old Pasta Piazza restaraunt. The carpet is still in rather good shape.
In MGM, there is a food service location near Indiana Jones called the Dip Site. The sign has been altered from saying "Dig Site #1138." 1138 is a reference to George Lucas' first film, and is used in some capacity in almost all of his subsequent films as an inside joke.
There is a picture representing Jim Henson as a Muppet hanging from the rafters of the MuppetVision pre-show.
The inflation platform for the Sorcerer Mickey balloon used in Sorcery in the Sky is still there and was, until recently, visible to guests. It's the large structure on the back of the Great Movie Ride show building, roughly opposite of WWTBAM/One Man's Dream that now has a large advertisment for the latest Disney movie on it. Before the ad was put in place, you could still clearly see the pipes labeled "Inflation" and some of the old fireworks launch tubes.