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