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.
null nullah nill knoll nelly knell knolly nellie nielli niello nil noel noil nolo nail nala kneel newly noily
bull full hull cull gull lull mull null pull dull