One of my favorite games in recent years has been Anno 1800. One of the many aspects of the game are long production chains, and oodles of items. This is something I set out to emulate. One thing that is a bit annoying about all the Anno items is that you are basically forced to have every item somewhere in your production. You can't progress if you skip production of an item because your next level of citizen has so many requirements. Obviously, this is part of the challenge, but I want the player to choose their own way of making money. If they want to play without mining a single resource, or play with only farms, or play without using managers, for whatever reason, I don't want to force the player to work with things they don't have any interest in. Thus, I set out to make an obnoxious number of items. Just over 350 at the moment, with 1000 more ready and waiting.

Items can only exist in the inventories of countries, and in the inventories of transport vehicles. There are no "Global" items.

Each item in the game has their own dictionary, which is nested within a very large dictionary called "all_items"

An item entry in all_items will look like this:

I tend to be a bit shy when it comes to sharing my code (...script) as it is not my strong suit, but it best illustrates what is happening in the background.

Every item has a recipe, unless it is a raw resource, and every item has an output, starting default market value, and market sensitivity

One of the great weaknesses of the game is the balance of going further down the production chain. It simply is not worth it for some things. One of the adjustments that will happen in the next update is auto-buying goods will receive a mark-up (more than the 5% the market already has, probably closer to 50%) so that there is an incentive to go to the beginning of a production chain instead of just buying the 2nd to last items in the chain and cranking out Electric Vehicles, and STILL making a profit.

I will also be looking at the recipes and outputs, along with values to make sure they make more sense.
This all before adding (too many) more items.
The most time consuming part of adding items is creating/finding the icon. I have been collecting licensed art for years, and have thousands of icons I can use, but a lot of this stuff is not something you are going to find in an icon pack. (Gearbox Housings, PSUs, Copper Coils, etc.)

So I have a few options:

-I can make it. - This I have done for all the basic metal items from ingots, sheets, plates, rods, wire, mesh, coils. And a few random ones. I just make them in blender, and throw a material on them. Other ones, I download a model, and render it. (I only choose CC0 models, as keeping track of who to give credit to is a paaaaaain.)

-I can find it. - Sometimes people have the icon I need. Or they have art that I can pull an icon out of with some photoshopping. I am always sure they follow one of 3 criteria:
1. A license that I paid for, and can use the art how I wish.

2. A CC0 license that allows me to use it without giving credit.

3. Free, but requires credit, and giving credit is simple. (I have credits in my game where I give credit where it is due.) (Freepik has been very helpful here.)

Most of the icons are within that last criteria. This takes time, as often I am taking them from info-graphics about assembling the very objects that are being made in the game.

I should also mention, that while I consider myself an artist, I am not particularly skilled, and 2d art is the bane of my existence. It is a shame that the icons in the game are all very different and disjointed, I would love for one day getting them all in the same art style. I just simply lack the skill, and artists aren't cheap. (For good reason.)

That brings me to the modern elephant in the room. While I do believe there can be a time and place for AI generated art, my game is not it. So while I'm on the prowl for icons, half of the challenge is making sure AI had nothing to do with its creation.
(Note: My previous project, the hotel simulation, had plenty of ai generated 2d assets made with StableDiffusion... ZERO in this project.)

Upcoming:

DD6: Influence

DD7: Market

DD8: Library

DD9: Research

DD10: ???