Pontoons rhymes with:
cartoons, platoons, tunes, afternoon's, afternoons, baboon's, baboons, balloons, boons, cartoons, cocoons, coones, coons, croons, dunes, funes, goons, harpoons, impugns, june's, junes, koon's, koons, kuhns, kunes, lagoons, lampoon's, loons, monsoons, moon's, moons, noons, nunes, platoons, prunes, raccoons, rangoon's, runes, saloons, spoons, tunes, tycoon's, tycoons, typhoons, verboons
Pontoons sounds like:
painting, paintings, pandanus, pandemic, panting, pending, pentiums, phantoms, pointing, pounding