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.
guacos guaiacs gucks quacks cacaos cuckoos gags cogs cocos gowks kagus gooks cokes cocks cocas gawks cacas quags cooks gogos caucus quicks cocoas quakes cookeys cookies gawkies quaggas quokkas cox gox quickies
tacos guacos cos shackos fucous wacks ficoes macs laics jacks jocose cacaos cocoas vacs cogs fucose cocos whacks shakos locos mucosa geckos mucous pacas pacs raucous sacks sagos sickos decos dioicous lacks guaiacs macks locoes buckos lacs hacks quacks boocoos backs coys cows cosy cacas coss jockos jucos makos tacks coos mucose knacks packs racks wracks sacs scows dagos decoys wackos whackos chicos shacks yacks
guaco guaiac guck quack quacky