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.
dropped dripped drooped draped trapped tripped trooped trouped dropt dropout torpedo trippet dript
propped cropped dropped wrapped trooped dripped trapped rapped repped ripped roped rouped bewrapped crapped gripped groped grouped prepped rewrapped drooped frapped tripped trouped