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.
sharper chirper chirpier
carper warper sharper harper chirper wrapper chirpier proper crapper larruper groper griper grapier grapery drapery dorper roper rapper rapier raper puerpera draper trapper riper reaper
sharp sharpie sharpy charpai charpoy sherpa