Hound is a label for a big family of hunting dogs, not a single breed. Most hounds on adoption pages are scent hound mixes with Beagle, Coonhound or Foxhound ancestry: medium-sized dogs with long ears, short coats and a voice that carries. Sighthound types like Greyhounds and Whippets turn up less often.
Most are friendly with people and other dogs, and happiest when following their noses. They can also be stubborn, howl or bay, and wander off after a scent, so leashes and secure fences matter. Because ancestry varies so much, a dog's size, energy and voice tell you more than the label does. Expect a short coat with moderate shedding and a healthy appetite.