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.
spurred sparred spared spored spread spired speered speared supered speired spoored spiered spurt suppurate superroad sprite sparid spiroid sparoid sporoid zippered superadd separate spirt sport superette sprat sprit spirit sporty sprout seaport support
spurred purred parred parried poured pureed vapoured repoured sparred
spurrey spurry spur sparrow sparry