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.
croppies crappies croupes crops groupies creepies crapes crepes cripes croups gropes grippes croupous corps craps carps corpse creeps grapes gripes corpus carpus groups grappas carapace gorps grips kreeps
crappies croppies preppies rappees frappes harpies creepies grippes groupies sharpies
croppie crop crappie crappy croup croupe croupy