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.
gulls guls gulleys gullies gules galls culls cullis quells quolls guiles quills gallus gals cullies gallows cullays gallous gallies galleys galleass goalless quillais galliass goals glues galas gales gleys calls kills glass cauls glias glows glees gloss gaols quillaias glossa quails caules glossy callas coulis galeas glassy galahs caulis callus callose coulees queleas killies glassie collies glossae kellies callees goalies callous coalless coulisse keelless cols
bulls mulls nulls culls pulls gulls hulls dulls lulls fulls ghylls ghouls molls boules hollas kills maills falls jills fillos caules guls miauls hells caulis hullos villas sulus jellos sauls hallos vills cellos mullas milles joules mills hellos phallus ballsy bills calls ollas balls pules shells pulse hauls tailles talls dills tellys ulus tolls walls wells challas chillis shuls yills duellos tules gills rouilles malls ills selles mells jells ells sills chollas fouls bolls pills dalles gallus doulas rills scillas follis hulas fills rilles hillos boulles mauls failles quells fellas quolls coulis galls gules callus buhls cells jouals niellos knells fells filles hills nills halls folles villus pulis duels hollos belles phyllos quills knolls lulus fuels paellas rules duals callas rolls lalls alls palls chills bells cauls mules lolls cullis souls polls puls tuilles shauls tulles dells dolls dulse tallis sells tells tills zills wallas wauls wills challis shills yells yules
gulley gull gully gul cull cullay cully gall galley gally golly guile