Thank You (Disc 1)
Go to the [Language Selection] menu of "Two Cars in Every Garage and Three Eyes on Every Fish" and select Blinky. You'll get an animated thank you note for David Silverman.
Additional Sketches (Disc 3)
Go to the [Language Selection] menu of "Bart's Dog Gets an F" and select the piece in his mouth. You'll get a sketch. On this sketch, select the head on the right for yet another sketch.
Go to the [Main Menu] of "Old Money" and move [Left] to select Grampa's fez. You'll get a sketch.
Go to the [Language Selection] menu of "Brush with Greatness" and select the painting. You'll get a sketch.
Additional Sketches (Disc 4)
Go to the [Language Selection] menu of "Three Men and a Comic Book" and select the paper slip the Comic Book Guy is holding. You'll get a sketch.
Go to the [Language Selection] of "Blood Feud" and select the eyes of the Olmec's head. You'll get Homer lay-out sketches. If you select the post-it note, you'll get more.
Deleted Scene Storyboard (Disc 4)
Go to the [Storyboards] for "Bart gets an F" in the [Special Features] section. Move until you reach page where the panel on the right is covered with a post-it note. Go to that post-it note. You'll get to see the storyboard for a deleted scene in that episode.