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.
popes pops poppies popsy poops pipes popsie poppas puppies peps pups pips paps pappies peeps pepos pupas papas pupus papaws pappus papoose pappose pappous pawpaws pappoose
hopes opes topes popes mopes ropes dopes lopes copes ops pes capes cowpeas buppies guppies puppies poops knops cowpies roups popsy nappes epees opus koppies cops veepees teepees bops hypes spews hippies spues japes soups peps tops yippies shops shapes chippies chappies wops wipes whoops whoopees types topis hyssops taupes topees copies mops dupes loupes oops rupees pies biopsy kops nappies poppies apes pews cepes coupes supes loops dopas tawpies napes hoopoes coops peas hops spies gapes poesy pappies copse loups jupes rappees kewpies pipes pehs hoops soaps rapes tapes pees ripes pops goops peso coups lops sipes spaes tepees sops topos fops toupees weepies whoopies whops woops chapes cheapies chops shoppes yipes yuppies
pope pop pipe poop poppa poppy bopeep epopee epopoeia