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.
groupies gropes groups croupes croppies grapes gripes croups grippes creepies crappies croupous gorps crops grips crepes crapes cripes grappas carps corps craps carpus corpse corpus creeps kreeps
groupies rupees harpies crappies creepies croppies croupes preppies drupes troupes sharpies
group groupie croup croupe croupy grope