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.
spread spared spored spired speired spoored spiered supered speered speared sparred spurred sprat superadd sparid superroad sprite spiroid sparoid sporoid zippered separate spurt sprit sport spirt superette suppurate spirit sporty sprout seaport support
copyread lipread spread superadd superroad pried poured papered peppered appeared vapored vapoured preed capered chippered coopered purred reappeared repoured sparred speered spiered spoored paired parade diapered parred pored parried paupered spored pureed loppered pared coappeared coppered kippered peered rapiered lippered lappered repaired spared speared speired spired spurred supered zippered tapered choppered
spree spar asper super spurrey spry spare sparrow sparry spear speer speir spier spiraea spire spirea spiry spore spray sprue spur spurry supra osprey