Plato
I actually thought of Augustus first.
Cleopatra and then Hammurabi, in that order, came to mind.
The Buddha.
Aristotle
I wonder why he seems to be a common choice.
Outside of Old Testament characters, Socrates
Pythagoras.
I’m a math teacher…
Cicero - and have no idea why
About six pharaonic names slid through my mind as I read the question. I’ll go with Seti II.
Alexander the Great, again. After all, he’s great.
Big Julie (thanks to Wayne & Shuster) jumped to my mind instantly.
Ooh, I think I can do Archimedes without looking him up. He died at the Roman capture of Syracuse, 212 BC. And he was pretty old at that point, probably over 70. I’m guessing he was born around 285 BC.
looks up
Wiki has him at ca. 287 BC - 212 BC. I’m awarding myself the point for that one.
(What? Yes, in fact, I am great fun at parties. Why do you ask? Actually, though, I’m usually crap at dates.)
As for the OP: My top three are Caesar, Hannibal (just because I’m into the Punic Wars at the moment), Alexander. After that, it’s a toss-up between a ton of people.
Vercingetorix?
Well, he’s all right. 
Yeah, that was mine as well.
Plato, the father of Western philosophy.
But then I’m a big fan of ancient Greek culture.
gautama buddha
The one I know best is Lao-Tze. Funny I didn’t think of him sooner.
Three
I guess my interpretation was who do we have the most evidence that they existed BCE.
Shamgar. From the Book of Judges (he killed a bunch of Philistines with an ox-goad).
He was kind of a running joke between me and a friend way back in the day for having two lines about him (“Shamgar who slew 600 (?) Philistines with an ox-goad. He too saved Israel.”) and that’s it. Badass enough to get mentioned but not enough to get a third line.
Hammurabi for me.
Themistocles.