Conversation so far:
What type of visual effects were used in this movie?
Using CGI techniques, it was possible to depict Gump meeting deceased personages and shaking their hands.
What other techniques were used?
To record the voices of the historical figures, voice actors were filmed and special effects were used to alter lip-syncing for the new dialogue.
Who was in charge of the visual effects?
Ken Ralston and his team at Industrial Light & Magic were responsible for the film's visual effects.
Are there any notable scenes of the movie where you can see the use of the visual effects?
In one Vietnam War scene, Gump carries Bubba away from an incoming napalm attack.
To create the effect, stunt actors were initially used for compositing purposes.

Question: Are their any other scenes?
Self-contained rewrite: Besides the Vietnam War scene, are there any other scenes in Forrest Gump?