In the Ancient Era, build Slave Auctions to gain the Slave resource, which allows you to build Laborer units. Until you reach the Renaissance Era, capture civilian or military units to transform them into maintenance free, but non-specialized workers.

Slave Trade: Based on UncivilizedGuy's mod.

Animals are typically much faster and stronger than early-game units, so be careful with early-game scouting! Killing these units yields substantial Food for your tribes.

Prehistoric Hunting: Using Wildlife Reborn as the base, Barbarians spawn animal units exclusively until around the Neolithic Era.

Affects the landscape of the world in the mid to late-game. Adds a background mechanic that measures global emissions by certain buildings and improvements.

Global Warming: Another mod by FramedArchitecture.

Doctor specialists can be put to work in your cities for extra Science and City Health. Your populace can be put at risk if a disease sweeps through your cities. Adds a new Health yield which affects city growth.

Health & Plague: Based on the Health & Plague mod by FramedArchitecture.

Will you build an empire that stands the test of time? Make your way through history as you find a foothold for your empire to unfurl. With this overhaul mod, you will start in the year 50,000 BC as a nomadic tribe doing their best to survive the harsh realities of the prehistoric world. I hope for it to become a communal project of sorts, akin to the Community Project (with which it was built alongside and is dependent on). After roughly 6 months of compiling code, graphics, and bug-testing, I'm finally ready to release this overhaul mod. I wanted a mod that covered all history to the present day and the future. For example, the Enlightenment Era mod by Pouakai only adds in the Enlightenment Era and is incompatible with other Tech Tree mods such as Prehistoric Era Reborn or Future Worlds. I noticed there were a few mods out there that expand the Tech Tree, but would only expand it in one way. For almost as long as I've played Civilization V, I've consistently felt that the vanilla Tech Tree was too short and was missing large swaths of human history.

Civ 6 future tech mod