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.
action auction
cation caution diction section rogation reaction negation location ligation coition kation action auction equation faction fiction vacation vocation coaction lection legation liquation locution paction recaution ruction suction taction cushion cushiony