Currently there are 22 native Telephoto Zoom lenses for OM System OM-1 and all of these lenses are autofocus (AF) type.
OM-1 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on OM-1.
Since OM System OM-1 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 11 Telephoto Zoom lenses with Weather Sealings.