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.
robot rowboat reboot rubout rebought rabat rebut robed rabbet rabbit rebait rebate rebody robbed rubati rabbity
robot bot towboat seaboot boat boot booty bota bott bout abbot about jabot obit reboot rowboat rubout sabot doubt showboat