Just starting out, I would focus more on how to make things and not so much on who to sell them too. (That comes easily later!)
Hooks, plant hangers, bottle openers, simple hot dog/marshmallow forks ect. all use basic forging and twisting skills and are always popular.
Believe it or not, nails sell well too, especially around Christmas ( stockings look nicer mounted on a forged nail, and if you Google "the Christmas nail ornamant", you'll find a little item that always sells)
Since you shoe horses, maybe a few hoof picks for customers...