You probably noticed that there isn't much to do in Bannerlord aside from fighting with lords as a power hungry lord or being a merchant and doing merchant playthrough. However, I always felt like the Merchant system in Bannerlord falls short. I'm not saying that it's bad or anything, but it could be spiced up a little. Bannerlord already reflects different cultures in Calradia with different troop trees, architecture and such, but it's not providing anything for more immersive trading gameplay. But this wasn't the case in the real world. There is a reason why trade routes like "Silkroad" were important for factions. It was granting access to unique items that they can sell for high prices. 
And for that purpose, I decided to create something. I wanted to reflect these cultures and this style in the Merchandise system. 
I decided to add culture specific new items. These items gets produced by the villages of that culture only and joins the circulation of the marketplace through your exchange or with villages selling it to their towns. I added 25 different items, both with their 2D Icons and 3D Objects. I won't show the 3D objects one by one but here how it looks on the list (and gemstones) 


And here is the full list of items' 2D icons in a row.

From left to right: Amber, Tin, Tea, Sugar, Sausages, Papyrus, Marble, Lead, Incense, Honey, Gold Ingot, Tobacco, Gold Ore, Gemstones, Dyes, Cosmetics, Copper Ingot, Copper Ore, Coffee, Citrus, Carpets, Bronze Ingot, Brass Ingot, Glassware, Tusk
And here is a list about the cultural distribution of these items:
Sturgia - Amber, Honey, Tusk, Tin, Lead
Vlandia - Copper Ingot, Brass Ingot, Gold Ingot, Papyrus
Battania - Sausages, Copper, gold, Bronze Ingot
Empire - Marble, Citrus, Cosmetics, Glassware
Khuzait - Tobacco, Sugar, Gemstones, Tea
Aserai - Dyes, Coffee, Carpet, Incense


And you can see the production of the villages next to game's native productions (I don't change anything on existing productions, but these are merely an extra unique production items)



Details of Trading
- Not all items have the same amount/rarity. Meaning that gemstones are extremely rare and gemstone-producing villages might not produce that item for days, even months whereas you can find citrus more commonly (since it's less rare)
- Your price depends on the distance of the item to that trader. Meaning that, if you just got some citrus from nearby Imperial town and trying to sell Battanians, they are likely to pay less. But if you can bring Tusk from far-distant lands of Sturgia to Aserain merchants, they will value this more and pay more. 
- Supply-demand curve is still in the game. Meaning that if you sell 100 citrus to a town, it's likely that they won't value it much because you just introduced abundant amount of citrus to circulation.
- Because villagers and caravans carry these items, it's likely that you loot some of these items after your battles as well - which, I believe, brings some more immersion.
- Luxury curve. When you are selling one of the items, the game is adjusting the rest of the item prices even when the transaction is still in progress. Like, you are selling dyes but your tobacco item's value is also decreasing in first-two sell - the reason of this is, you are changing the demand to luxury goods in that region and it's effecting all exotic items


Modular System
With v1.0.1, I created a modular system for mods that are adding new cultures, such as CEK. If you are using a mod that adds a new culture, you need to add this culture and it's production items to MerchantData/FactionData.xml 
Currently it looks like this

If you want to add a new one you have to add a new like like this (let's say we want to add a new culture "roman" )
<MerchantFaction culture="roman" production="marble,citrus,cosmetics,glassware" />Save the file and it should work.


Warning
Mods that are adding new cultures/settlements might not work as expected or not work at all. This mod is designed to revolve around Native settlements and cultures.
If you remove it halfway through the gameplay, it can cause problems because its adding new items. But if you have an existing save, you can add this mod in the middle of your playthrough.
Although I didn't see any direct effects of this in 25 year playthrough, it might have some long term effects on economy. Proceed with caution.

Installation
Extract the archive to a folder.
Take Merchandise folder and put it to your Modules folder (..steamapps\common\Mount & Blade II Bannerlord\Modules).
Load order doesn't matter, but don't be a hero, load it after Official modules.

FAQ
If you are getting "Cannot load .../Merchandise.dll" error
1. Go to Mount & Blade II Bannerlord\Modules\Merchandise\bin\Win64_Shipping_Client
2. Right click to Merchandise.dll, click Properties
3. Click Unblock on the bottom. OR follow this

If you want to use these icons and more in your commercial projects, make sure the check David Baumgart's excellent assets