Characters who start with the prefix "The":

Agreeable

• The Alligator King- title character in song, nobility
• The Amazing Mumford- official character name, used in dialogue and in the book Happy and Sad, Grouchy and Glad
• The Big Bad Wolf (Muppet Classic Theater)- common name in fairy tales
• The Big Bad Wolf- common name in fairy tales
• The Birdman- identified as such in credits and dialogue, reference to "the Birdman of Alcatraz,"
• The Birthday Bird- name in source text
• The Blimp- superhero name
• The Boss- character name, euphemism for Judaic-Christian deity God
• The Captain- character name
• The Cat in the Hat- name in source text
• The Cat- identified as such at Henson.com Featured Creature and in Designs and Doodles
• The Defroster - superhero name
• The Devil- common prefix for theological figure
• The Duchess- name in source text, nobility
• The Easter Bunny- full title for mythical figure
• The Gambler- title character in Kenny Rogers' song
• The Geefle- title character in "The Story of the Geefle and the Gonk."
• The Glutton- name in sketch title, Ed Sullivan intro
• The Gonk- title character in "The Story of the Geefle and the Gonk."
• The Great Potato- deity name
• The Grinch- character name in source text
• The Gryphon (Dreamchild)- character name in source text
• The Hat- identified as such in credits
• The Job Wizard- identified as such in credits
• The King - nobility title
• The King of Id- nobility, character name in source text, though often simply called "The King."
• The La Choy Dragon- introduces himself with "I'm the La Choy Dragon!"
• The Mad Hatter- name in source text, sometimes simply called "The Hatter."
• The March Hare (Dreamchild)- name in source text
• The March Hare (Muppet Show)- name in source text
• The Mudman- listed as such in books
• The Newsman- official character name, used in Palisades Toys' action figure and elsewhere
• The Pied Piper- character name in source fairy tale
• The Pink Panther- official cartoon character name
• The Prince of Phumph- nobility title
• The Procrastinator- superhero name
• The Queen of Phumph- nobility title
• The Queen- nobility title
• The San Francisco Earthquake- wrestling name
• The Six Dollar Man- name in dialogue, take off of "The Six Million Dollar Man."
• The Sphinx- common name for famous landmark
• The Spook- official character name in The Wizard of Id comic
• The Stepmother- common title in fairy tales
• The Swedish Chef- official character name, used everywhere
• The Watch Dog- superhero name
• The Whale- identified as such in presskit
• The Wiseman- identified as such in credits
• The Witch Doctor- title character in song
• The Wizard (Wizard of Id)- name in source text
• The World's Oldest Fraggle- always referred to as "The World's Oldest Fraggle" or occasionally "The World's Oldest"
• The Worm- identified as such in credits
• The Fastest Person in the Kingdom - called such in sketch dialogue
• The Smallest Person in the Kingdom - called such in sketch dialogue
• The Smartest Person in the Kingdom - called such in sketch dialogue
• The Tallest Person in the Kingdom - called such in sketch dialogue
• The Aristocrats- band group name
• The Benedictine Monkees - band name
• The Bookworms - band name
• The Country Trio- band group name
• The Cute and Fuzzy Four- band group name
• The Cute But Not So Fuzzy Four- band group name
• The Dirt Sisters- listed as such in articles about "City Kids."
• The El Sleezo Cuties- name listed in billboard
• The Electric Three- band name
• The Endangered Species Chorus Line- band name, mentioned in dialogue
• The Extremes- band group name
• The Falling Alfonsos- group name
• The Flying Zucchini Brothers- family group name
• The Gogolala Jubilee Jugband- band name
• The Leprechaun Brothers- band name
• The Merrill Lunch Hungerdunger McCormack All Accountant Marching Society- society name
• The Minstrels - band name
• The Muppet Glee Club - band name
• The Mutations- band name
• The Oinker Sisters- band name
• The Simpsons- official family name and show title
• The Squirrelles- band name
• The Tarnish Brothers- band name
• The Teeterini Family- group/family name
• The Three D's- band name
• The Three Elmos- band name, referred to as such in dialogue
• The Three Little Pigs- common fairy tale name
• The Danceros -- announced by Kermit specifically as "The Danceros"
• The March Hare (Muppet Show) -- from author's text
• The Newspig -- variation on The Newsman
• The Old Lady Who Swallowed a Fly- title character in song
• The Swedish Pig -- variation on The Swedish Chef
• The Busby Twins - family name, referred to as such in The Sesame Street Dictionary
• The Refined Young Cannonballs- band name
• The Sesame Street Cobblestones- band name, listed as such in album credits
• The Vile Bunch- band name, text from a Muppet Annual

Questionable

• The Monkey King- listed in credits as "Monkey King" but in dialogue and in print sources as "The Monkey King"
• The Sandwich- never addressed, not listed in credits
• The Cowardly Lion- listed in film credits as "Lion" and called "lion" in most dialog; but in most texts with "The"
• The Scarecrow- name with "The" in source text; listed as "Scarecrow" in film credits and called "Scarecrow" in dialog"
• The Wicked Witch of the East- name in source text; listed as "Witches" in credits
• The Wicked Witch of the West- name in source text; listed as "Witches" in credits
• The Wizard- named with "The" in source text; listed as "Wizard" in film credits
• The State of Indiana- refers to itself as "Indiana" in dialogue; Sam Eagle refers to it as "The State of Indiana" in disclaimer
• The Beetles- often listed in album credits as "The Sesame Street Beetles."
• The Female Singers- never addressed, fan-created name
• The Primitives- referred to as such in NY Times article, never actually used
• The RX Twins- also known as ""The Pak-Nit RX Twins."
• The Teppums- in contrast to The Muppets
• The Hipster- fan created name
• The Devils- listed in credits as "Devils"
• The Mop Dancers -- announced by Kermit as "Alfredo and Hildegard, The Mop Dancers"
• The Square- fan created name
• The Beast- referred to by Tosh Fraggle as "my beast" or "my pet beast."

No source (or at least not listed yet)

• The Announcer
• The Cheese
• The Christmas Turkey
• The Cloverland Dairy Cow
• The Dancing Clown
• The Eel
• The Elephant
• The Floating Face
• The Gagtoothed Groan
• The Germ
• The Glox
• The Lion
• The Messenger
• The Miller's Daughter
• The Music Store Owner
• The Old Woman Who Lived in a Nine
• The Showman
• The Snail
• The Snowman
• The Turkey
• The Babies
• The Bouncing Borcellino Brothers
• The Bun-Bun Brothers
• The Clodhoppers
• The Dancing Sacks
• The Fazoobs
• The Fuzz Brothers
• The Gingerbread Men
• The Mexican Hat Dancers
• The Motorettes
• The Muppaphone
• The Muppet Orchestra
• The Rock Lobsters
• The Snorers' Chorus
• The Snowths

Should lose the "The"

• The Frackles - Frackles
• The Snerfs - Snerfs
• The Stepsisters- referred to in dialogue as "Lisa" and "Mona" (or Mona and Lisa), should probably be moved