1) Dromon (Byzantine) - Extra attack ability in the early ages (and Greek Fire)
2) Javelin Thrower (Mayan) - Archer with extra defense, and enslavement skill
3) Crusader - With the Knights Templar, start cranking these out every 5 turns
Of course, the first two belong to civs that aren't included in the latest version. Maybe we'll see the Greek Fire return to the Byzantine shores in an expansion (?)