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.
rowdier rootier reedier ruddier readier ruder rider redder ritter raider rioter rudder router rotter redear ridder writer reader rudery rooter ruttier rattier radar retry rotor rater redry ratter retear retire retore rotary retiree reutter
bawdier rowdier dowdier faddier shadier headier woodier hoodier weedier giddier tidier lewder gaudier deedier ruddier leadier reedier moodier seedier muddier needier powder powdery readier beadier wader wider chowder shoddier
roadie rowdy crowd crowdie crowdy rod