@K311Y,
ten letter combos:angleworms, augmentors, demography, deutoplasm, downstater, downstream, endolymphs, godparents, greyhounds, gunpowders, gyroplanes, handsomely, headstrong, houseplant, hydroplane, hypodermal, largemouth, larghettos, lengthways, methylator, methyldopa, motherland, mouthparts, neuropathy, outlanders, outsmarted, personalty, petrolatum, playground, polyanthus, polywaters, postulated, pothunters, poultryman, poultrymen, promulgate, pulmonates, roundelays, sandlotter, sporulated, superwoman, transmuted, underplays, underplots, untowardly, upholstery, wanderlust, waterspout, wyandottes