There are some registries that accept horses (and sometimes ponies and mules) of almost any breed or type for registration.
For the purposes of this list, certain groups of horses that have an organization or registry that records individual animals for breeding purposes, at least in some nations, but does not clearly fall to either the breed or type categories are listed here.
This list does not include organizations that record horses strictly for competition purposes.
However, in some nations, particularly in Europe, there is a recording method or means of studbook selection for certain types to allow them to be licensed for breeding.
Prior to approximately the 13th century, few pedigrees were written down, and horses were classified by physical type or use.
Thus, many terms for Horses in the Middle Ages did not refer to breeds as we know them today, but rather described appearance or purpose.