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.
stepped steeped stopped stiped stoped stooped stupid seedpod stopt
stepped dapped dipped dupped tapped tipped topped tupped redipped steeped stopped tittupped