Count Fabulous is Draculaura's pet bat. He has a fondness for insects, which is a good thing considering Draculaura's vegetable garden attracts hundreds of them. He usually wears a pink heart dress and bow to please Draculaura. His color is black, and his them color is black(main), and pink(sub).
Crescent is Clawdeen Wolf's fuzzy little kitten. Like Clawdeen, Crescent has an alpha attitude and usually goes her own way, but she is also loyal to those important in her life. Her color is purple, and her eye is gold and black, as the werewolf/werecats. Her theme color is purple.
Crossfade is Holt Hyde's pet, a yellow and orange chameleon. He seems to enjoy music and accompanies his owner on night time strolls when they first move and get to know the place. Being the same person, Jackson Jekyll also owns Crossfade, but when with him Crossfade is green and yellow. His color, yellow-green and red-orange, his theme color is red orange(Holt Hyde) and yellow-green(Jackson Jekyll).
A cute little cobra with a not-so-cute bite. Hissette was an accidental stowaway in a gift from Egypt to Cleo de Nile and was swiftly adopted by the princess. She is normally dressed in gold bangles. Her color is light blue-green, and her theme color is also light blue-green.
Lagoona Blue's pet piranha is normally quite friendly despite her species. Lagoona carries her around in a special fishbowl purse. Her color is pink and light pink, her theme color is pink.
Nightmare is the fire-breathing horse of Headless Headmistress Bloodgood, functioning both as a pet and an assistant. Nightmare is a neurotic wreck of a horse, but intensely loyal to her owner and appreciative of kind gestures.
Perseus is a two-tailed black and orange rat owned by Deuce Gorgon. Deuce's mother was never pleased that her son named him after her enemy, and she once threatened to turn the rat into a paperweight if he kept raiding the kitchen for cheese. His color is gold and grey, his theme is grey.
Qing is a qilin owned by Jinafire Long as a preliminary prototype, but now does not exist in the franchise.
Rhuen is a cheeky ghost ferret owned by Spectra Vondergeist. Her color is mauve and light purple, her theme is light purple.
Rockseena is a rough gargoyle bulldog owned by Clawd Wolf. Her theme color is grey, as her color is also grey, with red-rose eyes.
Sweet Fangs is Toralei Stripe's pet saber-tooth tiger cub, he is quite tough and can go through a ball of dragon thread a day. His color is orange and dark orange, his theme color orange.
Watzit is Frankie Stein's pet simulacrum. Like his mistress, he has been stitched together, in his case from the best parts of several other house pets. Watzit takes mostly after his dog components. His color is brown and hazel-gold brown. His theme color is brown (main), and gold(sub).
Frido is Rochelle Goyle's secondary pet to Roux. He is a fuzzy ball of fluff who appears to have no eyes or nose, but he is mainly based off of the a Gremlin from the movie The Gremlins, with similarities of the "do's and don'ts" of how to treat one from the Warner Brothers movie, The Gremlins. His name is literally based on the name "Fido", as long with an anagram for the word "fright". Frido also hibernates by shedding his skinless fur all the way, showing bones, but this is done more quickly after not following the rules how to take proper care of him.
The frogs are Lagoona Blue's pets at school since the day she saved them from dissection. Their numbers are legion and they eagerly help Lagoona whenever she asks them for it. So far they are the only additional pets to be made as a figurine in a doll set.
Smokey is Deuce Gorgon's pet dragon from when he was a little boy. Smokey was the first pet he had. While playing one day, Deuce accidentally petrified Smokey and because he had little control over his powers back then, the spell didn't wane after 24 hours. Smokey has been a statue for many years while Deuce waits, heart-broken but patient, until the day he can be reunited with Smokey.
On October 6, 2010, the student that hosts the Monster High Facebook account asked the visitors what kind of pet she should pick now that her parents finally allowed her to have one. The visitors could choose between a striped owl, a white hamster, or a pink mini-dragon. As revealed on October 20, 2010, the pink mini-dragon won the vote. The Facebook host referred to her pet as a "he".
Purrsephone and Meowlody previously had a pet canary, but one of them became allergic and so they had to part with him.
Invisi Billy used to have a dog, but he had to give him away because he couldn't walk him without people thinking the dog was a stray. Nowadays, Invisi Billy has a box which may or may not contain a cat.