Fiat's rhymes with:
acrobats, aerostat's, aerostats, aristocrats, badavatz, brickbats, bureaucrats, caveats, copycats, coseratz, democrat's, democrats, democrats', diplomat's, diplomats, diplomats', doormats, formats, habitat's, habitats, laundromats, plutocrats, polecats, pussycats, rosenblatts, technocrats, thermostats, thundercats, wildcats, wombats, ziggurats
Fiat's sounds like:
faddis, faddish, fades, fads, faiths, fates, fatigue, fatigues, fats, fatties, fatuous, fauteux, fayed's, feats, fed's, fedak, fedex, feds, feeds, feith's, feitz, fetch, fetches, fetish, fetsch, fetsko, fettes, fettig, fetus, fetuses, fetz, feuds, feutz, fides, fifths, fifties, fifty's, fitak, fitch, fites, fits, fitts, fitz, fitzco, fitzhugh, food's, foods, foods', foodways, footage, foote's, fotis, foutch, fouts, foutz, fudge, fudgy, futch