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.
fours furs fores furies forays feuars foresaw firs foresee furioso ferrous furrows furious ferreous frass fiars fries feres fears frees furze fires fairs froes faros furzy force frows frise fares frays fraise frouzy frisee ferias frowsy vrouws faeries fairies farrows ferries phoresy various friz vars
fours pours giaours lours yours ours tours hours sours ors aurous noirs sorus moras houris coirs hoars horse mores pooris currs cooers hoers gaurs horsy ores course buras goers bores bourse furious sieurs cirrous knaurs pursy burrs roars noris kouros guars corse kurus yores toros choirs wooers urus vrouws torso torrs torse zoris toras durrs dures douras dors shoers chorus queuers doors puris arouse gorse ferrous rouse cures lores curs serious lauras feuars cerous cors suers purs morse boras parous nurse purrs kors curious torsi porous serous curse koras soars furs oars kauris auras soras roues murrs mures torus auris cores bursa burs lures carouse grouse various carious crouse muras moors gorsy boors horas burse boars pores aures knurs mors loris suras euros ruers rearouse fores ferreous buhrs sores purse churrs hydrous shores doers dorrs dorsa duras duros gores torous tores tors ursa whores worse chores gurus
four for fur fora foray fore forwhy furrow furrowy furry fury afore