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.
snivel sniffle sniffly synfuel sniffily snuffily synovial sinful snaffle snuffle snuffly sinfully snowfall
snivel naively navel nival novel nonnovel unveil