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.
spiry spry spray spier spire speir spurry sparry spirea seepier spar sappier spurrey spiraea spur soppier soupier soapier sapphire sprue spore sapor spare spree super spoor spear speer supra sopor sapour sapper sipper soaper supper sparrow zappier zippier
spiry pry ropier pray cuppier apery apiary prey peppier repair pappier popery pier nippier pair sappier mopery soapier soupier loopier spier goopier foppery vapory spry zippier dippier dupery tippier typier whippier chippier napery papery copier roupier quippier ropery coopery coppery hoppier hippier japery peppery rapier happier pipier spire nappier kouprey mopier seepier loppier soppier lippier speir gappier spray zappier diapir dopier tapir topiary weepier whipray choppier