I was going to suggest Mythic Greece for Mythras, but it still doesn't actually exist.
An alternative for Mythras, if a fantasy Greece analogue is close enough for your needs, is Shores of Korantia for the Thennla setting. Technically, something called orcs do exist in the setting, but they are fat, foreign, human slavers with a reputation for violence and depravity. I'd say Korantia is much closer to Classical Greece than their neighbour the Taskan Empire is to Rome.