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.
gawping gaping gapping capping coping cooping copping couping cupping keeping kepping kipping quipping
gawping yawping ping lipping hooping louping cupping hopping gapping rouping heaping jeeping piping supping lapping rapping hoping sapping gipping japing repping cooping copping siping keeping moping kipping whapping happing yapping shipping wapping chopping cheeping topping wiping whopping souping whipping knapping ripping loping zipping typing pupping tipping pooping duping taping nipping dipping gaping soaping hipping riping pepping fopping reaping aping beeping wrapping hyping quipping mapping leaping pingo coping roping raping jauping bopping gypping lopping couping kepping looping oping seeping capping piing peeping napping dapping dupping doping pipping tapping popping tupping zapping sipping mopping spuing wheeping hypoing whooping whupping toping chapping chipping upping shaping shopping weeping yauping sopping yipping