He is as straight as a die.

She is as thin as a wafer.

He was gay as a lark, singing and dancing all day long.

Finding true love is as rare as a four-leaf clover.

Why don't you stuff a sock in it and let someone else talk?

She told him to stick a sock in it when he wouldn't stop talking.

He let out a fart in a wind storm.

He was like a fart in a windstorm, completely unnoticed.

I could eat a brick

He threatened to hand someone his head on a plate if they crossed him.