Placemat rhymes with:
compumat, diplomat, doormat, format, laundromat, acrobat, aerostat, aristocrat, autocrat, babysat, bobcat, brickbat, bundesrat, bureaucrat, butterfat, carlstadt, caveat, chitchat, clarostat, compumat, copycat, d'etat, darmstadt, democrat, diplomat, doormat, eberstadt, eizenstat, estedat, farhat, format, habitat, inverlat, karstadt, kitcat, laundromat, lestat, muskrat, parmalat, plutocrat, polecat, pussycat, ronstadt, rosenblatt, technocrat, thermostat, thundercat, tomcat, urstadt, verhofstadt, wesat, wildcat, wombat, yediyat, ziggurat
Placemat sounds like:
placement, placenta, placentia, plasmodia, playcount, pleasant