I am presently looking for an accessible music/radio app that arranges pieces/songs by topic/theme. For example, I might want to look up songs about "space" or "aviation" or "the sea" or "sailing". I am looking also for an app that might also suggest new music to me on these and other topics/themes. It would also be preferable if you could also select by genre and/or by artist. Does anyone know of any apps that would fit this description?