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.
kasha cashaw cash gash quash cashew cashoo cushaw cosh gosh gush
kasha pasha sha ash leash bash mashy ashy pacha fash shay shaw pshaw sash quash dacha dashi deash washy shah poisha shea geisha gash bashaw lash mash gnash pash cashaw hash cushaw rash cash sashay dash dashy wash wisha