My guess is that they are synonymous with currency futures, as futures used to be known as commodities. Only a guess though. I've never heard the term "commodity currencies" before.
A few to start with - Australian Dollar, South African Rand, Canadian dollar ... These countries have economies that are heavily weighted to resources / commodites / mining / beers. Typically as a global expansion takes hold commodities like copper (the economists metal) and other base metals, and gold etc appreciate in price [ checked out copper chart lately ? ]. [ As a side, Canada is also a net exporter of oil. ] This together with the USD shitting itself has helped these currencies to some nice gains .