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.
mockup makeup
backup mockup lockup checkup cockup fuckup pickup kickup cup scaup lookup wikiup coup teacup beaucoup takeup makeup recoup hookup wickiup scup shakeup
mock moc mack mick mickey moke muck mucky amok smock smoke smokey smoky