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.
guilder guiltier golder glider quilter gladder killdeer gauleiter kilter colder glitter coulter clowder caldera gloater gladier coleader cloudier glittery gleetier collider colluder colter kelter kultur clatter clouter clutter culture
builder guilder milder wilder gilder moulder soldier holder older colder jilter molder alder collider killdeer colluder lader wielder golder bouldery blader gelder philter lieder balder deluder shoulder slider welldoer welder boulder folder solider bowlder polder glider caldera moldier milter quilter solder tilter aulder mouldier melder kilter bolder filter fielder eluder elder wieldier shielder yielder