Invisibility cloaks attract the attention and capture the imagination. The theory behind invisbility cloaks applies to waves; light is the area that gets most publicity, but other type of waves can be treated in the same way, including siesmic waves and acoustic waves.
Thermal applications have also been proposed. As pointed out by recent viewpoint for Physics, "Heat is governed by diffusion and therefore does not propagate in wavelike form..." Thermal cloaks have been experimentally demonstrated, including two thin 3D cloaks by Han et al. and Xu et al. Hence, this may help extend "transformation optics" into other areas where diffusion is significant, such as "electricity, tomography, or chemical diffusion"., in a