One of my dictionaries defines aphorism as a short pithy statement or maxim. I’m not sure if one can consider them a literary form, but I delight in them.
“It is as easy to dream a book as it is hard to write one.” (Balzac)
“Man shall not live by bread alone.” (Matthew 4:4)
“You can pretend to be serious; you can’t pretend to be witty.” (Sacha Guitry)
“Happy families are all alike; every unhappy family is unhappy in its own way.” (Tolstoy)
“Man is least himself in his own person. Give him a mask and he will tell you the truth.” (Oscar Wilde)
“Power is much more easily manifested in destroying than in creating.” (Wordsworth)
If I can slip them into my own writing it gives me pleasure.
“A sailor may choose the wind to ride out of seaport, but the wind has a mind of its own.” (True Confessions of Charlotte Doyle)
“The easiest part of being a parent is loving your child. The hardest part is convincing them you do.” (The Most Important Thing)
“The cure for unhappiness is this: What a person needs is always more than they say.” (What Do Fish Have To Do with Anything?)
“The more I knew of the world the more I knew I knew it not.” (Crispin: Cross of Lead)
“People are freer in America. But there are more tears.” (City of Orphans)
“Roads at night are always new.” (Night Journeys)
“Asking someone to say they love you is like buying yourself a birthday present. It’s more than likely exactly what you want. But it must make you feel awfully sad to get it.” (Sometimes I Think I Hear My Name)
Readers are welcome to supply their own favorite aphorism in the comments.