It was posted a few pages back, I think from the PartyElite first impressions video:
Ok. Here are my initial thoughts on all the civ unique bonuses in the screenshot. Obviously, the numbers could change between now and release.
Babylonians
Philosophers of the Wild: +2 science per extension on settlement
I think extension refers to when you expand your city's radius with a quarter. So this gives you a bit more science every time you make your city bigger. So going "tall" and making your cities really big and sprawling will give you a bunch of extra science.
Egyptians
Grand Planners: Modify artificial wonder production cost by -25%
This is a simple bonus that makes wonders cheaper to build. It should be noted that this does not mean you will built more wonders like it might imply in civ. You can't just spam more wonders. In Humankind, I believe "influence" determines when you get to select a wonder to build. So this bonus will only trigger from time to time, when you get to select a wonder to build. But this bonus will mean less time devoting your cities to wonder construction. This bonus might mean that you won't need to assign as many cities to wonder construction, allowing your other cities to continue to build other stuff while you finish a wonder. Definitely a nice bonus but obviously only works when you are building wonders.
Harappans
Fertile Inundations: +2 food and +2 industry on river
Not a huge bonus but if you build all your cities on rivers, your cities will get a nice little boost that will help when they are brand new.
Mycenaeans
Brutal Upbringing: +200% experience on unit
This feels like a monster bonus for military players. Get into a lot of fights and you will end up with some tough veteran units.
Mayans
Tireless Spirit: +3 industry on exploitation
Not sure what exploitation is but extra industry is good.
Persians
Cyrus' Shadow: +2 Administrator count
Basically, 2 more cities before you hit your cap. This bonus basically let's you expand more. I like it a lot. Considering how expansion works, I can see Persians really aggressively claiming regions as fast as possible and getting a wider empire faster.
Romans
Legion's Finest: +3 Army cap
Not sure if this means armies can have +3 units or you get +3 armies before hitting your generals cap. The former would mean stronger armies. The latter would mean more armies on the map. Of course, you still need to build the units to fill the armies and terrain may not guarantee a victory. But having bigger armies or more armies is certainly a great bonus that will make Rome the military power they should be. Either way, this sounds like a great bonus.
Mauryans
Guiding Light: +10 science per independent people under patronage, +10 faith per independent people under patronage on the capital's city center
Independent People are like City-States in civ. So this is the equivalent of +10 science and faith per City-States that you are the Suzerain of. Depending on how many Independent Peoples there are, this could be a nice bonus or not. The extra science is nice of course. Not sure about faith since we don't know how religion works in the game.
Huns
Formidable Steeds: +3 combat strength on cavalry unit, +3 combat strength on mounted nomad
Straight up stronger calvary. Makes sense for the Huns. Could definitely make the Huns a powerful cavalry military civ as they should be. I could see players spamming cavalry units and blitzing the map.
Goths
Nimble pillage: +5 combat strength from ransacking on army
Not sure what "ransacking on army" means. But this sounds like a situational bonus where you get extra combat in a particular situation. Could be useful.
Celts
Druidic Lore: +3 food on exploitation
Same as the Mayan bonus but extra food instead of extra industry. Personally, I prefer extra industry. With the way HK does pop growth, the +3 food might not even trigger faster pop growth.
Carthaginians
Hard Bargainers: Modify all constructibles buyout cost by -50%
This sounds like cheaper buying buildings with gold. -50% is big. If you have a lot of money, you should be able to simply buy buildings. This sounds like a great bonus.
Greeks
Socratic methods: +2 science per researchers on settlement
With the way pop management works, this bonus could give a lot of science for bigger cities. For example, if you have 5 pop assigned to science, that's an extra +10 science. Nice! I like it. I always love more science.
Aksumites
Horn of Plenty: +5% money per number of trade routes
Obviously designed for your trade route civ. But with a lot of trade routes, this could be a monster bonus.