Friedrich Nietzsche

Diogenes, Father of Cynicism, also like Epictetus, and Pyrrho.

Diogenes.

Lord Krishna. And the book, "Shrimad Bhagwat Gita", popularly known as Gita.

He doesn't really qualify as "ancient" but Niccolò Machiavelli is one of my faves.

Socrates man. Love that guy

“The best purpose”

King Solomon

Yoda

I never tire of either Aristotle or Plato and still read them.
But so many of the Ancients still have the most profound things to say to us.
Good question, Sage!

plato

Has to be the father of philosophy. My boy Socrates. Not only for his extemely wise teachings but also for his courage and bad ass attitude.

Mark ass Aurelius