Keystone rhymes with:
freestone, blackstone, bloodstone, bluestone, blystone, bridgestone, brookstone, brownstone, capstone, cherrystone, cobblestone, cornerstone, coverstone, curbstone, eyestone, featherstone, finestone, firestone, flagstone, folkstone, freestone, gallstone, gemstone, gladstone, goldstone, gravestone, greenstone, greystone, grindstone, hailstone, headstone, instone, johnstone, levinstone, lightstone, limestone, livingstone, lodestone, medstone, milestone, millstone, moonstone, poundstone, redstone, rhinestone, richstone, sandstone, silverstone, steppingstone, tombstone, touchstone, waterstone, weatherstone, wedgestone, whetstone, whitestone, yellowstone
Keystone sounds like:
kaden, kadumi, kasten, katayama, katayan, katen, kathan, kathman, katona, katuni, katyn, kaydon, kazakhstan, kazakhstana, keaton, keeton, kesten, ketema, keteyian, ketney, ketone, keyton, khatami, khazakhstan, kidman, kidney, kittaneh, kitten, kittman, kodama, kootenay, kwitny