as alike as two peas in a pod
as angry as hell
as bald as a coot (coot - a bird with a white patch on the head)
as bent as ... (corrupt or dishonest)
as big as an elephant
as big as a battleship
as big as a whale
as big as a house (said of a person physically large and overweight)
as big/large as life (used to describe the surprise of seeing someone)
    I never expected her to come to the wedding but there she was, as big as life.
    I looked up and there she was, as large as life.
as bitter as gall
as black as hell/coal
as black as pitch (pitch - wood tar or resinous goo from tress used to caulk the seams of ship for waterproofing)
as blind as a bat
as bold as brass (usually negatively)
    John went right into the principal's room, as bold as brass, and complained about the bully
as brave as a lion
as bright as a button
as busy as a bee/beaver/cat on a hot tin roof
as calm as a millpond (usually of water)
as cheap as dirt
as clean as a whistle/a (new) pin
    spick and span (about a place) very clean and tidy
as clear as day
    It was as clear as day that he would win the elections.
as clear as mud (very difficult to understand)(ironical, sarcastic)
    His speech was as clear as mud.
as clear as a bell (very easy to hear)
    I could hear their whispers as clear as a bell.
as clear as crystal
as close as the grave
as clumsy as an elephant
as common as dirt
as cold as marble/ice
as cold as steel/stone
as cool as a cucumber
    Even after the suspension he was as cool as a cucumber.
as cunning as a fox
as dark as death
as dead as a dodo/doornail
    The cat in the road was as dead as a doornail
as deaf as a post
    Our grandpa is as deaf as a post.
as different as chalk from cheese
as drunk as a lord
as dry as dust/a bone
as dull as ditch water
as easy as anything/pie/ABC/falling off a log
    piece of cake
    My Chemistry exam was a piece of cake.
as fast as a deer
as fat as a pig
as fit as a fiddle
as flat as a pancake
    In some parts of India, land is as flat as a pancake.
as free as a bird
as fresh as a daisy
as gentle as a lamb
as good as gold
as good as new (in good condition again, after not working well)
    I gave my camera for repair, and now it's as good as new.
as green as grass
as happy as a lark
as hard as nails
as harmless as a dove
as heavy as lead
as high as a kite
as hot as fire/hell
as hungry as a wolf/bear
as innocent as a lamb
as large as life (See 'as big as life' above)
as light as air/a feather
as like as two peas
as long as your arm
    He has a list of qualities as long as your arm.
    There was a list of complaints as long as your arm.
as mad as a hatter (From Mad  Hatter in "Alice’s Adventures in Wonderland")
as mad as a hornet
as mean as a snake
as nutty as a fruitcake (completely insane)
    nuttier than a fruitcake
as obstinate as a mule
as old as the hills
as pale as death
as plain as a pikestaff (very obvious)
as plain as day/the nose on one's face
as poor as a church mouse
as poor as dirt
as pretty as a picture
as proud as a peacock
as quick as lightning/a flash/a wink/silver
as quiet as a church mouse
as regular as a clockwork
as right as rain
as safe as houses
as scarce as hen's teeth
as sharp as a razor
as sick as a dog, parrot
as silent as the dead/the grave
as slim as a willow
as slippery as an eel
as sober as a judge
as solid as a rock/the ground we stand on
as sound as a bell
as sour as vinegar
as steady as a rock
as stiff as a board
as straight as an arrow
as strong as an ox
as stubborn as a mule
as sturdy as an oak
as sure as hell/death and taxes
as tall as a giraffe
as thick as thieves
as thin as a stick/rake
as timid as a rabbit
as tired as a dog
as tough as old boots/leather/nails
as ugly as sin
as warm as toast
as weak as water
as welcome as a skunk at a lawn party (not welcome - ironic, sarcastic)
as white as snow/a sheet
as white as a ghost
as wise as Solomon/an owl

(as) black /sure /... as hell (used to emphasize an unpleasant characteristic)
    He is as mean as hell