2 syllables:
batres, caters, craters, fratres, freighters, gaiters, gaters, gators, graters, haters, laters, maters, matres, paters, platers, praters, raters, skaters, slater's, slaters, stater's, staters, stators, taters, traitors, waiter's, waiters

3 syllables:
creators, curator's, curators, debaters, debator's, deflators, dictators, dilators, donators, dumbwaiters, equators, fellators, gyrators, headwaiters, hydrators, inflaters, inflators, levators, locators, migrators, mutators, narrators, pronators, pulsators, relators, rotators, tailgaters, testators, translators

4 syllables:
abdicators, abnegators, abrogators, activators, actuators, adulators, agitators, alligators, allocators, alternators, amputators, animators, annotators, applicators, arbitrator's, arbitrators, arbitrators', aspirators, buccinators, calculators, calibrators, carburetors, celebrators, circulators, cogitators, collimators, commentator's, commentators, commutators, compensators, concentrators, confiscators, cultivators, decorators, dedicators, defalcators, defecators, delegators, demarcators, deprecators, depredators, desecrators, designators, detonators, devastators, deviators, dominators, duplicators, educators, elevators, emulators, epilators, escalators, estimators, excavators, expiators, extirpators, fabricators, fascinators, flagellators, formulators, fornicators, forty-eighters, fumigators, generator's, generators, gladiators, hesitaters, hibernators, illustrators, imitators, incubators, inculcators, indicators, infiltrators, inhalators, innovators, instigators, insulators, integrators, irrigators, isolators, iterators, lachrymators, legislators, legislators', liquidators, litigators, lubricators, masturbators, mediators, meditators, mitigators, moderators, motivators, mutilators, navigators, nomenclators, nominators, numerators, obligators, operator's, operators, operators', orchestrators, oscillators, peculators, penetrators, percolators, perforators, perpetrator's, perpetrators, pollinators, postulators, procreators, promulgators, propagators, radiators, regulator's, regulators, regulators', remonstrators, renovators, resonators, respirators, rotavators, ruminators, scintillators, second-raters, separators, sequestrators, simulators, speculators, stimulators, stipulators, subjugators, summercaters, superfreighters, supinators, syndicators, tabulators, terminators, tolerators, trafficators, valuators, venerators, ventilators, vindicators

5 syllables:
abbreviators, abominators, accelerators, accumulators, adjudicators, administrator's, administrators, administrators', adulterators, amphitheaters, amphitheatres, annihilators, anticipators, appreciators, appropriators, articulators, assimilators, attenuators, authenticators, bronchodilators, capitulators, co-operators, co-ordinators, coagulators, cogenerators, collaborators, commemorators, conciliator's, conciliators, consolidators, contaminators, cooperators, coordinators, deactivators, decelerators, defibrillators, deliberators, delineators, demodulators, denominators, denunciators, discriminators, disintegrators, dissimulators, ejaculators, elaborators, electroplaters, eliminators, emancipators, emasculators, enumerators, equivocators, eradicators, evaluators, evaporators, exaggerators, exterminators, facilitator's, facilitators, illuminators, impersonators, incarcerators, incinerators, incorporators, inoculators, inseminators, interpellators, interrogators, intimidators, investigator's, investigators, investigators', invigilators, manipulators, monochromators, negotiator's, negotiators, negotiators', obliterators, officiators, originators, oxygenators, perambulators, perpetuators, pontificaters, precipitators, procrastinators, prognosticators, proliferators, reciprocators, refrigerators, rejuvenators, repudiators, resuscitators, retaliators, totalizators, vasodilators

6 syllables:
differentiators, excommunicators, neuromodulators

7 syllables:
chernobyl liquidators

9 syllables:
list of roman amphitheatres