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.
ripened reopened repined repinned repugned repand repent repaint
lippened happened ripened cheapened opened deepened reopened pend paned weaponed penned deponed speaned peened spend spined peined repined pined depend append upend opined spendy