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.
croupes croups crops groupies croupous croppies cripes groups crapes gropes crepes corps carps craps crappies creepies carpus corpus gripes creeps corpse grapes grippes carapace gorps grips kreeps grappas
troupes croupes ropes roups rupees croups gropes groupies groups liriopes hyperopes pyropes drupes towropes tropes
croup croupe croupy crop croppie group groupie