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.
pups pupas pupus pops pips paps peps puppies peeps popsy poops pepos papas pipes popes pappus papaws popsie poppas papoose pappies pappose pappous pawpaws poppies pappoose
jaups coups cups loups pups roups soups sups dups tups ups whaups whups yaups yups