Small (1mm sized) water droplets or ice suspended in air form clouds. Since these particles are suspended in a gas and have properties more consistent with that of a gas, I think that are not truly soft matter.
Actually, there must be some interesting physics involved to produce the wide range of shapes of clouds. For instance, why do some appear to have boundaries, instead of simply diffusing? A less-than-reliable (i.e. not peer-reviewed) source raises some interesting questions about what causes clouds (see ). Water droplets are much denser than water, so even updrafts of wind or atmospheric drag forces would not be enough to suspend them. Instead, the author claims that the air between water droplets is warmed by the heat of condensation when the water vapor forms a suspension in the atmosphere. However, even this additional information does not explain the morphology of clouds.
Another non-journal article about the physics of clouds  explains how some aspects of clouds are fractal-like due to atmospheric turbulence, but daily temperature cycles, spatial variations in the earth's surface (e.g. land-sea boundary), and Benard cells  can introduce additional structures.