| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| Unnamed-2011 | bay | c | 2011 | 643094100110834 | 0383-3 Dubai To Dubai | 0484-2 Masara | Thoroughbred | Maistrenko Stud |
| Unnamed-2011 | chestnut | f | 2011 | 643094100110646 | 0702-4 Sharp Intake | 1004-3 Aliana | Thoroughbred | Maistrenko Stud |
| unnmed (died) | bay | c | 2023 | 643090000618397 | 0967-5 Solo Again | 1328-3 Dialina | Thoroughbred | Mr Stepanishin P.A. |
| Uno | bay | f | 1953 | Orator | Unterwegs | Thoroughbred | Germany | |
| Uno Best | bay | f | 1944 | Sir Gallahad III | Level Best | Thoroughbred | USA | |
| Unoaprile | bay | c | 1977 | Kalamoun | Ussin | Thoroughbred | Ireland | |
| Unobstructed View | d.-bay | f | 2003 | Yes It's True | Thimble Island | Thoroughbred | USA | |
| Unofine | grey | f | 2014 | 643090000168631 | Macho Uno | 3914-6 Fineness | Thoroughbred | USA |
| Unopposed | bay | f | 1991 | Sadler's Wells | Midnight Lady | Thoroughbred | Great Britain | |
| Unorna | d.-bay | f | 1892 | Galopin | Thoroughbred |