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.
sirs sires sirees sirras sieurs sris sers sierras sirrahs sirrees soirees sores soars suers sours suras cires sorus soras seers saris saros seres sears cirrus serows serous serosa sarees surahs serais surras series zaires serious serosae serries sorrows cirrose souaris sauries cirrous seeress surreys
airs lairs chairs weirs deairs sirs pairs noirs mirs mairs kirs fairs keirs coirs heirs hairs vairs firs wairs whirs choirs
sir sire siree sirra sirrah sirree