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.
crops croups croupes carps corps craps croupous croppies crepes groups corpus gropes carpus crapes cripes corpse creeps crappies creepies groupies gorps grips grapes gripes kreeps grappas grippes carapace
crops hydrops drops props chirps hydropsy tropes roups towropes groups herpes droops perps rips craps trips sharps preps croups grips liriopes bewraps preops pyropes sirups dorps dropsy urps gorps wraps troops raps turps gropes traps rewraps ropes carps carpus corps corpse chirrups tarps warps corpus harps larrups burps syrups drips reps hyperopes fraps sherpas
crop croppie grope croupy croupe croup cripe crepy crepe crepey crappy crappie crape crap carpi carp scroop