
Just a poll about the presocratics, Plato (Socrates is tied to that option) and Aristotle, and ending with Epicurus, so of Greek philosophy from the 7th to the mid 4th centuries BC. Of course some of the philosophers concurrent with Aristotle are missing (eg Theophrastos, Antiphon of Athens, or other tied to Plato)

Options are (mostly by chronological order) :
1) Thales (city: Miletos)
2) Anaximander (Miletos)
3) Anaximenes (Miletos)
4) Pythagoras (Samos/Croton)
5) Heraklitos (Ephesos)
6) Xenophanes (Kolophon/Elea)
7) Parmenides (Elea)
8) Zeno (Elea)
9) Empedocles (Akragas)
10) Melissos (Samos)
11) Democritos/Leukippos (Abdera)
12) Anaxagoras (Klazomenae/Athens)
13) Protagoras (Abdera/Athens)
14) Socrates/Plato (Athens)
15) Diogenes (Sinope/Athens/Corinth)
16) Aristotle (Stagyra/Athens/Pella)
17) Epicuros (Samos/Athens/Lampsakos)
18) Other or Aliens (Delta Draconis/Other/Othermost)
I thought of writing at least some characteristic concept(s) of each one, but likely it would not say that much in case it was not already known, so this is just a poll made of atoms dancing in an infinitely larger void.
My favorite would be Protagoras (judging from what can be inferred of his work by Diogenes Laertius, and even the hostile Plato/Socrates and Aristotle), and also Heraklitos and (somewhat) Zeno/Parmenides.