As regular as clockwork
As right as ninepence
As right as rain
As safe as houses
As safe as the Bank of England
As scarce as hen's teeth
As sharp as a tack
As sick as a dog
As sick as a parrot
As silent as the grave
As skinny as a rake
As slippery as an eel
As slow as molasses in January
As sly as a fox
As snug as a bug in a rug
As sober as a judge
As solid as a rock
As soon as you like
As sound as a bell
As straight as a die
As straight as an arrow
As strong as an ox
As stubborn as a mule
As sure as God made little green apples
As sure as eggs is eggs
As sweet as pie