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.
copays cops cowpeas coops copes copse coups copies coypus coupes koppas capias cuppas copious cowpies coypous caps cups kops capes capos goops kapas kappas coppice koppies
pays copays spays repays pas nappas cuppas papas kapas paps kappas lipase pase huppahs capias pupas sepias spacy spas dopas teapoys tepoys chuppahs repass pass bypass poppas spaes sepoys pias papaws papacy napas opahs cowpeas pacy koppas pawpaws paws peas nipas tapas tepas upas chuppas
copay cop coop cope copy coup coupe cowpea cowpie coypou coypu scop scope