Currently there are 8 native Macro Prime lenses for Sony A6600 and 5 of these lenses are autofocus (AF) type.
A6600 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on A6600.
Since Sony A6600 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 4 Macro Prime lenses with Weather Sealings.