Essentially, all EM waves can be seen as radio waves, as they all have wave lengths, frequencies and energy, which are associated with each different type of EM waves - plus each of these EM waves can transmit & receive audio & visual signals…
Yes, I know that when people talking of radio waves, we are usually referring to AM, FM, VHF, UHF and other modulation waves, that can be used for radio & tv, but this is the 21st century, microwave and laser (light) can also transmit audio & video signals as well as data.
Light as in visible light, including the spectral colours in light are radio waves that are visible and seen. Whereas other EM waves have wavelengths that are outside the range of human perception. Laser are essentially light, and laser can be used to transmit audiovisual signals through medium, such as fibre optic cables. Whereas microwave can be used to transmit audiovisual signals from tower to tower, to allow audiovisual communication between two or more people on their mobile phones or tablets.
Yes, there are natural radio waves or EM waves, and much of them from our Sun - visible waves and invisible waves.