I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
natters netters nutters knotters knitters noters niters natures neuters kneaders niteries nitros nadirs nitres needers nitroso nitrous nodders notaries notorious nutrias
betters litters vetters petters quitters nutters ritters rotters whetters knotters potters reutters chitters otters jitters whitters cotters gutters hitters chatters totters tatters getters tetters titters yatters wetters lotters shutters natters setters putters cutters jotters letters butters ratters shatters netters fitters fetters mutters bitters sitters hatters knitters patters batters matters utters dotters baiters heaters tooters footers vetoers terse waters boaters peters steres tears haters deters daters neuters heteros maters beaters metiers ottars miters outers eaters rooters shooters routers cheaters goiters kiters tuateras pewters touters auteurs coaters niters tiers looters caters oaters writers titers puttiers taters mooters paters cottars liters cottiers couters rioters toters hauteurs loiters quieters pitiers hooters powters meters cooters bettors uterus doters citers souters waiters suiters gaiters meteors teeters noters dieters biters raters quoters steers seaters shouters wheatears daughters pouters attars gaters voters retears sheeters quittors meeters
natter gnattier nattier neater netter nutter