| Name | Color | Sex | Year of birth | Microchip | Sire | Dam | Breed | Breeder |
|---|---|---|---|---|---|---|---|---|
| The Massey Mare | black | f | 1700 | Masseys Black Barb | Thoroughbred | Great Britain | ||
| The Matriarch | chestnut | f | 1935 | 995 Cyclonic | Dail | Thoroughbred | Great Britain | |
| The Merapi | chestnut | c | 2021 | 643090000484791 | 1476-7 The Riddler | 4340-6 Milaia Feia | Thoroughbred | Mr Mutaev Sh. V. |
| The Mermaid | bay | f | 1853 | Melbourne | Sea Weed | Thoroughbred | ||
| The Mersey | chestnut | f | 1859 | Newminster | Rigolette | Thoroughbred | Great Britain | |
| The Minch | bay | f | 1926 | Heather Belle | Thoroughbred | USA | ||
| The Minstrel | chestnut | c | 1974 | Northern Dancer | Fleur | Thoroughbred | Canada | |
| The Minx II | bay | f | 1914 | Irish Lad | Artless | Thoroughbred | France | |
| The Miser Ccarve | bay | c | 1841 | Thoroughbred | Great Britain | |||
| The Mole | c | Thoroughbred | Great Britain |