Herakles, the Greek Hero-God
Herakles on drachm of
Alexander the Great
Both gods and heroes were worshipped in ancient Greece, each with their special class of rituals and respect paid. It is in the case of Herakles, who straddled - or perhaps bridged - the line between the two, that we find the key exception, where worship has taken frequently on both forms. The body of legends on him is vast, and of course, not always consistent; depending on which one is consulted, Herakles' "level of divinity" may vary. Still, given that many legendary figures were based on real personalities, one might wonder if this may not apply to the great hero as well - and indeed it is sometimes conjectured that he could have been a Bronze Age historical figure, perhaps a king from Tiryns in the Peloponnesos.
In any case, having emerged beyond historical recognition from the Dark Age into Homeric Archaic Greece, his veneration spread throughout the Greek realm - from "his own" pillars (i.e. Gibraltar) in the West, to the farthest reaches of Hellenistic India. As mentioned, this cult took many forms - some of which we know regrettably little about today, like the special games and festivals in his honor, known as Herakleia. But his depictions on coins are plentiful yet subtly different enough, and quite collectable once you go past the other, more specific Heraklean themes presented here.
Search for coins featuring reverses with a couple of interesting exploits of Herakles.