There are not many Farmers in Cornwall, while more generally the words peasant and smallholder did not give rise to surnames. Sometimes, the absence of these names is linked to their frequency in medieval times. If there were a lot of peasants then calling John or Joan ‘Peasant’ would be of little help in distinguishing them from other Johns and Joans.
However, some status and occupational names had become surnames before the 1500s. Bond was a name for a peasant farmer or a husbandman who owed various forms of labour service to his landlord.
Heard is supposed to have been a name given to a herdsman, someone who tended animals, not necessarily cattle.
Although the surname Shepherd was not sufficiently numerous (or confined to Cornwall) to be included in my The Surnames of Cornwall, several Shepherds are found in sixteenth century records.
There is a definite eastern bias to Bond. The status of a bondsman may have been relatively rare in the Cornish-speaking west with lighter and less feudal service demands. The other specialist agricultural occupational names are English and we might expect a similar bias towards east Cornwall. However, although there was a catch-all word in Middle Cornish for a herdsman or shepherd (bugel) this was not found as a surname. More widely, with the exception of Angove (Smith) Cornish-language occupational names were rare and those that did exist, most of them relating to cloth or food production and building, disappeared over the course of the 1500s and 1600s.