This is a list of background characters, sorted by their incidental model numbers. SpongeBob SquarePants has a large amount of background characters, who are identified by the artists and animators by individual model numbers. Many of the background characters' model numbers are included on storyboards and animatics. Many of them are also listed on sheets as tweeted by Vincent Waller. Some characters were removed from the sheets, mainly between the third and fourth seasons.
Most background characters have two models: one for their daytime color palette and another for their nighttime color palette (for example, Fred's palettes are labeled "001-DAY" and "001-NIGHT").
Several of the original incidental characters were removed from the model sheets after the third season. Their numbers are known from storyboards. Specifically, numbers 33, 35, 61, 62, 70, and 71 are known from the storyboards of "Christmas Who?."
These incidental model sheets were uploaded by Vincent Waller to his Twitter on February 8, 2018.