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.
koppas kappas kops koppies kapas cuppas copays cowpeas kips cops keps keeps coops copse coups kepis copes goops capias coupes coypus copies copious coppice cowpies coypous guppies kewpies quippus
cuppas kappas chuppas nappas poppas koppas pas typps pass pappus quippus kapas paws repass spaes tapas copays nipas pips pupas repays sepias spas dopas tepas upas spays pias chuppahs pase apps cowpeas pays nappes pawpaws opahs pops lipase repps peas hippos peps papaws napas paps huppahs pups bypass papas capias shoppes