| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Summertime Showers | d.-bay | f | 1987 | Raise a Native | White Reason | Thoroughbred | USA | |
| Summing | bay | c | 1978 | Verbatim | Sumatra | Thoroughbred | USA | |
| Summit | chestnut | f | 1918 | Ultimus | Torpenhow | Thoroughbred | USA | |
| Summit Park | bay | f | 1995 | A.P. Indy | Gold and Purple | Thoroughbred | USA | |
| Summoned | chestnut | f | 1978 | Crowned Prince | Sweet Life | Thoroughbred | Avstraliia | |
| Summonit | bay | c | 2020 | 643090000419473 | 1071-5 Sweet Ducky | 5430-7 Tam View | Thoroughbred | Gudermessky Hippodrome |
| Sumota | bay | f | 2023 | 643090000704679 | Will Take Charge | 6669-8 Matsumoto | Thoroughbred | Studfarm "711" |
| Sumoto | bay | f | 1990 | Mtoto | Soemba | Thoroughbred | Great Britain | |
| Sumpter | chestnut | c | 1818 | Sir Archy | Thoroughbred | USA | ||
| Sumptuous | d.-bay | f | 2005 | Hennessy | Belle of Perintown | Thoroughbred | USA |