How many movies have Frank Welker and Robert Alvarez collaborated on?

They have worked on 3 movies together! Their first movie together was Pinocchio and the Emperor of the Night (1987) while their highest rated movie together was Scooby-Doo on Zombie Island (1998). They have not worked together since The Flintstones: On the Rocks (2001). They are most known for their family films together.