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.
cosh gosh cash coach cooch couch cuish cushy cushaw cashaw cashoo cashew gash gush cache catch cutch gushy kasha ketch quash
bosh josh cosh gosh mosh nosh posh tosh whoosh woosh sh