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.
papaws pawpaws papas paps papacy pappus pappose pappous papoose pappies pips peps pups pops pappoose peeps pepos pipes poops popes popsy pupas pupus poppas popsie poppies puppies
paws pawpaws papaws pas koppas napas nipas papas pews opahs pase pass poppas paps kapas repass ripsaw spaes spays dopas tepas whipsaw chuppas nappas pias pays peas capias copays cowpeas cuppas gawps kappas bypass pupas lipase pows huppahs repays sepias spas spews tapas upas chuppahs yawps
papa papaw pap pappi pappy pawpaw