Valentine has also written song lyrics for his street stories, including "Paleontologist Calypso," "Think It Through," "Feelings Come and Feelings Go," "Grover Can Do It All," and "One Thing at a Time." Valentine has written episodes of various animated series including My Little Pony: Friendship Is Magic, The Fairly Oddparents, Ultimate Spider-Man, Marvel's Avengers Assemble, Doc McStuffins, and Bubble Guppies. Outside of television, Valentine has written plays for the stage and worked in puppet theater.