The ones that never get an outting, the chance to use them has never arisen.
For instance, from the many useless facts in my brain:
The phrases "Not enough room to swing a cat" and "Don't let the cat out of the bag" are actually about a whip "Cat O' nine tails" which was kept as a warning and punishment on ships.
Oh and snails can sleep for three years.
Please release some of yours.