In the interwar period, and especially after WWII, bands in the areas of Kraków and Tarnów started to use the Polish accordion, nowadays replaced by the accordion. Also popular to a degree was the helicon accordion. Already in the 1930s, but mainly after WWII, Rzeszów-based bands started to include the hammered dulcimer. The instrument had usually been played by Jewish and Romani musicians before, and was incorporated into Polish traditional bands as a regional instrument as a result of the folkloric revival, and because of purely musical reasons as it fits well in-between the melodic and bass instruments.
Until WWI, in east sections of Lesser Poland one could spot, if rarely, the hurdy-gurdy (lira korbowa), an instrument played in the modern era in Europe and in Poland by wandering musicians performing narrative songs, a rare occurrence in Polish music. Up until WWII hurdy-gurdy players were relatively numerous in Ukraine. Nowadays, the instrument is played by musicians of the folk revival.
Wedding Dance; The Band of Wincenty Firmowski from Januszewice: Wincenty firmowski, violin, Stanisław Puchała, double bass, Jan Uraziński, drum; rec. Warsaw 1969; Sources of Polish Folk Music
Krakowiak from Wesołów; The Band Kamionka from Łysa Góra: Józef Wróbel, violin, Kazimierz Wróbel, violin, Władysław Panek, clarinet B, Józef Janowski, trumpet, Jan Ochoński, double bass; rec. Warsaw 1969; Sources of Polish Folk Music
Bride's tune; The Sowa family band from Piątkowa: Wojciech Sowa (1911-1977), violin, Józef Sowa (1903-1978), violin, Józef Sowa (1904-1983), hammered dulcimer, Piotr Sowa (1911-1997), double bass, Jan Krztoń (b. 1937), clarinet in B-flat; rec. Kazimierz 1976; Sources of Polish Folk Music