Countless rhymes with:
pointless, warrantless, atlas, cutlass, doubtless, ductless, effortless, flightless, fruitless, hartless, heartless, limitless, listless, meatless, meritless, pilotless, pointless, restless, rootless, spotless, tactless, tasteless, thoughtless, ticketless, warrantless, weightless, witless
Countless sounds like:
candles, candlish, centel's, chontales, cosmetology