Johann Pachelbel

Pachelbel wrote a large body of organ and keyboard music and one canon, and the canon has entirely swamped the rest.

The Canon in D exists in more arrangements than possibly any other piece in this catalogue — string quartet, solo piano, guitar, wedding ensembles of every configuration, and every grade from beginner to concert. It was written for three violins and continuo, and everything else is an arrangement. Check what you are getting.

The organ music is genuinely worth knowing and largely ignored: the chorale preludes are accessible to an organist of moderate ability and are good introductions to a style that Bach later took much further. All of it is out of copyright.