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.
prodder prouder prudery parader parroter porter prater predry pretor partier pearter praetor parador purtier parterre portiere prettier perter perdure portray
prodder brooder reorder order grodier gridder cruddier crowder corder broodier broider redder broader border ruddier rudder ridder prouder shredder