The available article content consists only of website navigation elements and a title, with no substantive text describing which mainstream artists reportedly created avant-garde music or the reasoning behind the list. Far Out Magazine appears to have published a piece under this title, referencing Yard Act in a "Cover Story" tag, but the actual list and accompanying commentary were not present in the retrieved text.

As a result, no specific artists, albums or examples can be confirmed or summarised from the source material provided. A full and accurate rundown would require accessing the complete article directly from the Far Out Magazine website.