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.
grapery grapier griper groper gripper grouper gripier crapper crappier grippier carper creeper crepier cropper crupper creepier croupier
grapery drapery warper trapper draper grapier crapper carper frippery harper wrapper ropery reaper rapper rapier raper sharper
grape grapey crape grappa grapy gripe gripey grope