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.
needier needer kneader nettier nuder nadir niter nodder neater nitery netter neuter nattier knitter niterie nittier nuttier gnattier knottier nitro noter natter nutter knotter
needier seedier deedier reedier weedier beadier lewder feeder hoodier heder faddier eider reader deader tidier wedder gaudier needer headier ruddier seder giddier cheder shedder metier heeder tedder header dowdier readier beader leader seeder ceder rowdier bawdier bedder muddier redear redder kneader moodier lieder leadier weeder woodier shadier shoddier