The lands of Skyrim, once the civil-war and the Dragon crisis began, became to be a site of extensive banditry and lawlessness, in the choas you took up the trade of horse thief, stealing mounts from unsuspecting victims, perhaps from farms or even daring to steal from the camps of the opposing Legion and Stormcloak forces. Despite the threat of the death penalty, perhaps it was desperation, thrill or simply the call of fortune that drove you to this lucrative but dangerous profession. Your time as an erstwhile horse thief has given you plenty of experience in the saddle and a knack for acquiring and appraising other people’s mounts, pets, and vehicles among other things. This particular set of skills has become very lucrative for you by working for the underground for a local guild of thieves and other shadowy organizations.
Black-Market Breeder You know how to find people who are always looking for stolen animals & vehicles, whether to provide for animal pit fights, or to supply some desperate rogues the means to get away faster on mounts during an illegal job. This contact not only provides you with information of what such animals & vehicles are in high demand in the area, but also offers to give you favors and information (DM choice) if you bring such animals & vehicles to them.