Currently there are 37 native Telephoto Prime lenses for Canon 70D and 30 of these lenses are autofocus (AF) type.
Canon 70D doesn't have a sensor based image stabilization system but 15 of these Telephoto Prime lenses features optical image stabilization.
Since Canon 70D has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 16 Telephoto Prime lenses with Weather Sealings.