| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Sound Sweep | bay | f | 1966 | Thoroughbred | USA | |||
| Sound Track | c | 1957 | Whistler | Bridle Way | Thoroughbred | Great Britain | ||
| Sound Wisdom | bay | f | 1992 | Pirate's Bounty | Kaylem Ho | Thoroughbred | USA | |
| Soundings | bay | f | 1983 | Mr. Prospector | Ocean's Ansver | Thoroughbred | USA | |
| Soundtrack T N | chestnut | c | 2016 | 981020019508610 | City Zip | Style Show | Thoroughbred | W. S. Farish & E. J. Hudson, Jr. Irrevocable Trust |
| Soundwave | f | 2008 | Friends Lake | Echo Echo Echo | Thoroughbred | USA | ||
| Sounion | bay | f | 1961 | Vimy | Esquire Girl | Thoroughbred | Great Britain | |
| Sour Apples | bay | f | 2017 | Lemon Drop Kid | Miss Red Delicious | Thoroughbred | USA | |
| Source of Life | bay | f | 2002 | Fasliyev | Asnieres | Thoroughbred | Ireland | |
| Source Sucree | br. | f | 1940 | Admiral Drake | Lavendula | Thoroughbred | France |