[ ] A Tribe of the North (European Mercenaries arrive at your disposal) [May expend gold for purchasing unique units at a much higher cost {150% tot heir gold cost}]
[ ] A Tribe of the West (Greco-Romans Mercenaries arrive at your disposal) [May expend gold for purchasing unique units at a much higher cost {150% to their gold cost}]
[ ] A Tribe of the South (African Mercenaries arrive at your disposal) [May expend gold for purchasing unique units at a much higher cost {150% tot heir gold cost}]
[ ] A Tribe of the East (Asian Mercenaries arrive at your disposal) [May expend gold for purchasing unique units at a much higher cost {150% to their gold cost}]
[ ] A Tribe of the Water (Polynesian Mercenaries arrive at your disposal) [May expend gold for purchasing unique units at a much higher cost {150% to their gold cost}]
[ ] A Tribe of the Distant (South American Mercenaries arrive at your disposal) [May expend gold for purchasing unique units at a much higher cost {150% to their gold cost}]
[ ] Added a fully developed writing system (Unlocks Writing for free) [very rare tho]
[ ] Zero and One System (Unlocks Mathematics for free) [very rare tho]
[ ] The Hero of {Cityname} (Free Great Scientist) [very rare tho]
Maybe for Version 6...