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.
grapier grapery gripier crappier grippier griper groper gripper crepier crapper grouper creepier croupier carper creeper cropper crupper
rapier grapier chirpier trippier droopier drapery syrupier preppier gripier raper rapper reaper ropier roupier wrapper carper harper crapper crappier creepier crepier croupier grapery grippier sirupier draper drippier trapper warper sharper