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.
wraps raps reaps rapes reps rips rappees repos roups repps ripes ropes repays repose ripsaw rupees repass rupiahs reoppose repousse
raps wraps jaups capos caps gapes gaps gawps capes kapas laps leaps napes knaps paps apes soaps daps tapes taps whaps chapes cheapos shapes yaups neaps apos japes lapis reps heaps rips reaps rapes papas haps napas naps maps lapse apps apse baps saps zaps tapas tapis waps whaups chaps cheaps yaps yawps
wrap rap trap drape grapy grappa grapey grape crappy crappie crape crap frappe frap reap rappee rape drapey warp