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.
sepoy seepy spy seep spay sepia soapy soppy soupy sappy sip spa cep sap sop sup zep cepe sipe soap soup spae spew spue supe
tepoy sepoy heapy pepo peppy repay repo seepy teapoy weepy cheapo