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.
sepia spa seep spay seepy sepoy sip spy sop sap sup cep zep cepe sipe soap soup spae spew spue supe
sepia pia kepi repay rupiah tepa weepie