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.
prefer preaver prefire proffer proofer purifier prover privier porphyry
reefer prefer refer briefer forever turfier gruffier terrifier gruffer surfier griever rarefier verifier proofer proffer roofer reefier rifer purifier riever surfer reoffer draffier reifier troffer refry wherever