Solar energy. The sun's energy comes to us as radiant heat, clearly there is nothing between sun and earth that can carry the heat energy by other means.
An electric toaster operates largely by radiant heat, though there will also be some conduction through the air from the element to the bread. The same applies to a radiant electric fire with a glowing red element.
Examples of radiant energy include: gamma rays, visible light, X-ray and radio waves. Radiant energy is known to be electromagnetic in nature and it travels in transverse waves. So the heat that burns you from the campfire can be one form of this energy.