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.
stoper stooper stopper steeper stepper stupor
doper stooper toper stoper taper stopper typier steeper duper tippier tipper tapper dopier topper dupery diaper deeper dapper bediaper stepper dipper dippier didapper
stop stope step steppe stipe stoop stoup stowp stupa stupe estop