Although the "Imagine" music video has shown up in many places since, the other videos in this film have rarely been seen outside of this film although the footage from them has usually been made up to be other Lennon videos in compilations such as Lennon Legend.
Fred Astaire made a cameo appearance in John Lennon and Yoko Ono's "Imagine (1972)" film, escorting Yoko through a doorway; after one successful take, he asked to try again, believing he could do a better job.
The white chess set from the "Don't Count The Waves" segment is Yoko's art piece "Play It By Trust" which has showed up in many of her exhibitions since.
The path John and Yoko are seen walking down during the opening scene (and the first notes of Imagine) is the path leading up to their British home at Tittenhurst Park. They would move to New York shortly after they had filmed that sequence.