Undertones rhymes with:
overtones, baritones, blackstone's, bridgestone's, cherrystones, cobblestones, cornerstones, firestone's, flagstones, folkstone's, gallstones, gemstones, gladstones, gravestones, hailstones, halftones, headstones, keystone's, keystones, limestones, livingstone's, madstones, milestones, moonstones, overtones, redstone's, reflectone's, rhinestones, tombstones, waterstone's, yellowstone's