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.
readier reader reedier raider redder ruddier rattier rowdier radar redry rider rater ruder ratter redear rioter rudder retire retear rudery redrew writer ridder ritter reutter ruttier retiree rootier retry retro redraw retore rooter rotary rotter router
headier readier beadier leadier shadier rowdier dowdier muddier sadder ladder meatier header beader bawdier woodier faddier madder deader badder lauder nadir padder raider fader adder wadder baiter kneader waiter ruddier weedier tidier needier seedier lader gaudier reedier aider hoodier deedier gaiter wader reader peatier loader leader moodier gadder matier giddier shader shoddier
read radii radio readd ready redia rediae roadie bread bready oread dread tread uredia rad red