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.
coups coupes cups cops copes copse coops copies coypus cuppas copays caps kops coypous copious cowpies cowpeas capes capos goops quips koppas quipus capias coppice guppies koppies quippus gaps keps kips
loups soups roups coups ups ops popes cops opus copes coupes pupus coops loupes coypous lupous ropes biopsy quips lupus copious soaps mopes tops yaups chops knops hoops pious goops topis lopes taupes dupes dopas supes mops opes hopes poops pappous oops cups jupes pops upas whops hops loops copse pups jaups lops pupas popsy whaups woops bops hyssops sops spouse sups dopes dups topes topos tups fops kops whoops whups wops shops yups
coup coupe cop cup coypu scope scop cuppy cuppa cowpea coypou cowpie copy cope copay coop scup