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.
copiers copers coopers coppers copperas capers copras copperahs cooperies coappears cappers coprahs cuppers coppras capoeiras capris gapers caprice gawpers keepers kippers koupreys quippers cuprous
piers spiers rapiers copiers rapers sippers hopers tapers coappears lepers gawpers suppers cuppers peers peres nippers appears copers wipers lappers ropers topers coopers peris diapirs pipers capers whappers yaupers shoppers chippers whoopers uppers tappers dopers zippers spires papers speirs loopers loppers knappers gippers copperas spears japers peepers rappers reappears rippers wrappers shapers pairs mopers kippers shippers operas dippers repairs nappers toppers sappers quippers cheepers apers gyppers pears hoppers reapers soapers moppers pries coppers cappers mappers vipers jeepers keepers whippers lopers hoopers heapers hypers gapers poppers peppers paupers boppers speers zappers tapirs lippers yappers leapers beepers perse supers diapers dupers tippers weepers whoppers choppers yawpers
copier cooper coopery coper copper copperah coppery