Can't go wrong with a bit of Horace Andy either

I don't know whether The Upsetters classify as reggae or Ska, either way they're very good. Or, were very good.

The Upsetters were classed as Ska.

The Upsetters were a session band for Lee Perry. The Barrett Bros, Sly & Robbie, all the major innovators of reggae riddim played in it. But I can't recall them doing any ska. It was roots and dub mostly.

Other great session groups include the Aggrovators (Bunny Lee's), Roots Radics, and the Revolutionaries.