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.
coopery cooper coppery coper copier copper goopier coappear copperah caper copra coppra capper cupper coprah cuppier kouprey capoeira gaper gawper keeper kipper gappier quipper
coopery popery mopery ropery peppery coper opera copier mopper copper japery cooper hooper goopier mopier hoper soaper dopier toper whooper chopper hopper napery papery foppery perry lopper coppery loopier moper popper roper peery looper loper apery bopper ropier doper dupery topper whopper shopper per pry
coop cope coupe cowpea scoop scope cop