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.
sacs sacks sags sics secs skas soaks sucks scows sagas skuas sikas sakes socks socas sicks sagos sakis squaws sickos scouse saigas sax sukkahs sickies sickees skis suqs sequoias suks segs skies skews seeks sooks skees sokes souks scuzz segos sikes sykes
vacs guaiacs lacs macs pacs sacs