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.
rappen rappini ripen rapine rapini reopen ripieni ripieno repin repine repugn
happen keppen shippen kippen lippen rappen pen peon pean pippin cheapen copen spean open loupen reopen ripen deepen pein shapen peen shippon
rappee rap drapey grapy grappa grapey grape crappy crappie crape crap frappe frap wrap repp reap rape drape trap