Currently there are 18 native Standard Zoom lenses for Panasonic GH4 and all of these lenses are autofocus (AF) type.
Panasonic GH4 doesn't have a sensor based image stabilization system but 10 of these Standard Zoom lenses features optical image stabilization.
Since Panasonic GH4 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 9 Standard Zoom lenses with Weather Sealings.