Currently there are 59 native Wideangle Prime lenses for Sony A6400 and 42 of these lenses are autofocus (AF) type.
Sony A6400 doesn't have a sensor based image stabilization system but 1 of these Wideangle Prime lenses features optical image stabilization.
Since Sony A6400 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 31 Wideangle Prime lenses with Weather Sealings.