| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Willathewest | bay | f | 2005 | Gone West | Willa Joe | Thoroughbred | USA | |
| Willesden | d.-bay | c | 1878 | Thoroughbred | Great Britain | |||
| 1010-5 William Creek | d.-bay | c | 2001 | William Lawrence | Whitney | Thoroughbred | Czech Republik | |
| William Lawrence | d.-bay | c | 1986 | Fappiano | Mesabi | Thoroughbred | USA | |
| William of Valence | br. | c | 1932 | Vatout | Thoroughbred | France | ||
| William Rufus | chestnut | c | 1900 | Melton | Thoroughbred | Great Britain | ||
| William The Thir | chestnut | c | 1815 | Thoroughbred | Great Britain | |||
| William The Third | bay | c | 1898 | St. Simon | Gravity | Thoroughbred | Great Britain | |
| William's Pride | bay | f | 1911 | William The Third | Stop Her | Thoroughbred | Great Britain | |
| Williams Forester | chestnut | c | 1750 | Crofts Forester | Looby Mare | Thoroughbred | Great Britain |