One of the things characters in a realistic world have to deal with are competing goods. No, not merchants undercutting each other in the marketplace. The plain (but not simple) fact that an item, location, or other resource might be profitably and reasonably used for one of several purposes, each of which may preclude other uses.
For example, damming a river may give hydropower and a lake for recreational boating, but it puts whitewater enthusiasts out of luck, and tends to imbalance the usual species of river fish because the water coming out the bottom of the dam will be colder than the sun-warmed river water. You can’t say one of these options is Bad and the other Good. Each of them are useful. Which is why arguments over them can be so fierce, and spawn a lot of potential conflict in-story.
Another example of competing goods is naturally colored versus white cotton. White cotton is probably the variety most of us are familiar with. Dyeing cellulose is never easy, but we’ve worked it out, hence why you can get your t-shirts in a rainbow of colors. The downside is… well, dyeing cotton is not easy, it involves a lot of chemicals, there are more pesticides and herbicides used to grow white cotton – in short, it is not exactly the most environmentally friendly crop out there.
Colored cotton has mostly been preserved as heritage varieties in odd places, although some companies like FoxFibre are trying to grow it on a larger scale for luxury products. It doesn’t need as much pesticides or herbicides, you can select varieties for a range of colors from a striking green to reddish browns, and so long as you like the color it needs no dyes at all.
It’s also legally banned from being grown in many states and counties, especially those that grow white cotton on large agricultural scales.
Cotton will apparently out-cross very easily, even with plants not close by. Farmers growing white cotton for the regular textile market do not want to find colored fibers showing up in their crops. It damages the value of their product. So they’ve passed laws to keep their business stable. As, you know, regular people wanting to make a living tend to do.
So for a fantasy setting, say it’s two different varieties of magical component herbs, each of which is specific to a particular kind of spellcasting. Who’s going to grow what? Which kind of magic is most useful? In particular, is one kind more useful for spells running a kingdom, while the other works better for the massive single-caster spells used by dragonslayers? Who decides what you can use, and what are the consequences if someone grows one variety in the territory of another? Things to consider!