In "Black Beauty" by Anna Sewell, who are all of the owners of Black Beauty?

There are nine owners of Black Beauty recorded in the fictional novel.  However, there are many more who come into contact with him throughout his life and have a dramatic impact upon him.
Black Beauty is born to Dutchess and owned by Squire Gordon of Birtwick Manor.  He lives there until his mistress grows ill and must move away.
Beauty is sold to the Earl of W--- of Earlshall Park, where he is well-tended until Reuben Smith enters the story.  Smith ruins Beauty's knees through careless riding.  The Lady of W--- cannot abide by a horse with such knees in her stables and he is sold again.
His next owner is unnamed and referred to only as the master of livery stables where horses are available for rent.  For the first time in his life, he is subject to continued substandard treatment until bought by a kind-hearted man who rented him once, Mr. Barry of Bath.
Jeremiah Barker, a cab driver, is the fifth owner of Beauty.  Barker treats him quite well and may have owned him throughout his life if not for his catching cold during a long evening wait.  Unable to continue the business, Barker passes Beauty on to another unnamed owner. 
The corn dealer and baker cares little for horses and sells Beauty to Nicholas Skinner, a harsh coachman.  Skinner abuses his horses and nearly kills Beauty with exhaustion and an overloaded coach.  Forced to sell him or allow him ample pasture time to heal, Skinner sells him at a London horse fair.
Farmer Thoroughgood, a kind fellow, and his grandson take a liking to Beauty and purchase him for a good sum.  Beauty is once again on the mend and when healed is brought around to his final home.  He is offered to the Ladies of Birtwick Manor, specifically to Miss Ellen.  The groom, Joe Green, recognizes Beauty's markings and everyone associated with the Manor is happy to see his return.
https://etc.usf.edu/lit2go/125/black-beauty/