A perfect companion dog

Breed groups argue that any dog in the working group type is inherently a "working" dog, while others argue that only a dog with an active occupation, either in a breed-related field (such as water trials for retrievers or herding trials for herding dogs ) or in a breed-nonspecific field that requires training and discipline, such as being
assistance dogs or participating in
dog agility, can be considered a working dog.
Dogs that have been chosen for traits that make a convenient pet are generally smaller breeds, and the tradition of keeping pretty dogs for no purpose other than to be court decorations stems back thousands of years to Chinese nobility. The
Pekingese and the Pug are both examples of canines chosen for their ability to be pets. In the case of the Pekingese, it was for their lion-like demeanor; for the Pugs, it was for their "lucky" wrinkles and their monkey-like face.
Other dogs that appear to be strictly a decorative or entertaining breed of dog originally also had jobs outside of their main companionship task, such as the
Lhasa Apso's job as a watch dog, or the delicate Yorkshire Terrier's exceptional rat catching abilities.

List of companion dogs
Affenpinscher
Alaskan Klee Kai
American Eskimo
American Hairless Terrier
Askal (Aspin)
Australian Silky Terrier
Australian Shepherd
Basset Hound
Beagle
Bichon Frisé
Biewer
Brussels Griffon
Bolognese
Boston Terrier
Bulldog
Cavalier King Charles Spaniel
Chihuahua
Chinese Crested Dog
Collie
Coton de Tulear
Cross-breed dog
Dalmatian
Dachshund
Dalmatian
Elo
English Toy Terrier
Eurasier
French Bulldog
German Spitz
Golden Retriever
Griffon Bruxellois
Havanese
Indian Spitz
Italian Greyhound
Japanese Chin
Japanese Spitz
Keeshond
King Charles Spaniel
Kromfohrlander
Lhasa Apso
Löwchen
Maltese
Manchester Terrier
Miniature Pinscher
Miniature Poodle
Miniature Shar Pei
Miniature Schnauzer
Mixed-breed dog
Papillon
Pekingese
Phalène
Pomeranian
Pug
Shetland Sheepdog (Sheltie)
Pembroke Welsh Corgi
Shih Tzu
Skye Terrier
Staffordshire Bull Terrier
Teddy Roosevelt Terrier
Tibetan Spaniel
Tibetan Terrier
Toy Fox Terrier
West Highland White Terrier
Xoloitzcuintli (Xolo or Mexican Hairless Dog)
Yorkshire Terrier