Korea:

Emblematic unit:
Geobukseon (Turtle ship) https://en.wikipedia.org/wiki/Turtle_ship 

Emblematic quarter: 

Seowon https://en.wikipedia.org/wiki/Seowon 

Poland:

Emblematic unit:
Winged Hussars https://en.wikipedia.org/wiki/Polish_hussars 

Emblematic quarter:
Zaluski library https://en.wikipedia.org/wiki/Za%C5%82uski_Library 

Russia:

Emblematic unit:
Streltsy https://en.wikipedia.org/wiki/Streltsy 

Emblematic quarter:
Posad https://en.wikipedia.org/wiki/Posad 

Ming Dynasty:

Emblematic unit: 

Treasure Fleet https://en.wikipedia.org/wiki/Chinese_treasure_ship 

Emblematic quarter:

Opera theatre https://disco.teak.fi/asia/the-ming-dynasty-1368-1644/ 

Ottomans:

Emblematic unit:

Kale Kob https://en.wikipedia.org/wiki/Ottoman_weapons#Artillery_gallery

Emblematic quarter:

Ottoman coffeehouse https://en.wikipedia.org/wiki/Ottoman_coffeehouse 

Ayutthaya 

Emblematic unit: 

Chang suk https://en.wikipedia.org/wiki/War_elephant#Indian_subcontinent 

Emblematic quarter:

Floating market https://en.wikipedia.org/wiki/Floating_market#History 

I agree with all the civilizations you mentioned, but since you are still four civilizations short, I decided to add them according to my ideas: Congo, Aztec, Spain, Sweden

But in this case, will there be a lot of European countries? Maybe it would be better to replace Sweden with Inca

zhugejingqi wrote:

But in this case, will there be a lot of European countries? Maybe it would be better to replace Sweden with Inca

While I have nothing against the Inca in the Early Modern age, their military technology would lack far behind other cultures in this era. Spain would have lance cavalry and arquerbuses, completely outmatching the Incas.

As for choice of emblematic quarters, we could have the: 
- Coca plantation (The Incas chewed coca leaves to decrease hunger and increase energy)
- Yupana house (A house to calculate things like crop yields, taxes. Basically an accounting house. They tied strings into knots which represented information. These strings could also be used to store information like history or literature) https://en.wikipedia.org/wiki/Yupana

Similarly for the Kongolese, the lack of horses and gunpowder would really make them vulnerable. I would propose Dahomey - since they received matchlock muskets in exchange for slaves. 

Emblematic unit:
Mino https://en.wikipedia.org/wiki/Dahomey_Amazons

Emblematic quarter:
Royal Palaces of Dahomey https://en.wikipedia.org/wiki/Dahomey#Arts
 

zhugejingqi wrote:

I agree with all the civilizations you mentioned, but since you are still four civilizations short, I decided to add them according to my ideas: Congo, Aztec, Spain, Sweden

Aztec are already in the game in the medieval Era

I say that both Spain and Portugal and also the Dutch deserve a place in the early modern era

Dutch and Venetians are kinda confirmed (for Venetians there is a small doubt)...with ships their unique units.

Spain, Poland, Russia, Ottoman Empire, Korea and Japan (last two are in the game for sure and early modern is the most suitable choice) are seems to have highest chances of appearing in this.

However, it gets trickier after it. Ok, we will have Germans and Americans in the Industrial era, maybe Brazil as well, but what about the rest. And what about the last era?

AndreyP wrote:

Dutch and Venetians are kinda confirmed (for Venetians there is a small doubt)...with ships their unique units.

Spain, Poland, Russia, Ottoman Empire, Korea and Japan (last two are in the game for sure and early modern is the most suitable choice) are seems to have highest chances of appearing in this.

However, it gets trickier after it. Ok, we will have Germans and Americans in the Industrial era, maybe Brazil as well, but what about the rest. And what about the last era?

last era or next era?