Here's some interesting data on Magnamund that will affect the NES. I've tried to add more elements of magic NES in this, and this is one of them I guess.
First of all, I need to elaborate on the
"age" system. The technological level you begin at, and most likely will stay on, is the equivalent of early iron age of OTL. However, natural metal deposits are rare (as are most important resources) making know-how less important than actually controlling mines and excavation sites. This is due to the depleting by the Ancients during their time, and the fact that they took with them much of their goods when they left Magnamund. The impact this has on the NES is as follows: you won't actually enter copper age until you gain access to copper (through mining or trade). Likewise, you enter iron age as soon as you discover iron. However, if you lose access to iron, you will revert back to copper age.
I understand the term "age" can be misleading, but it is primarily supposed to denote the strength of your military units. You might be techonologically advanced, and still be in copper age. However, there are of course benefits to being in iron age (since iron is more durable than copper) Oh, and if you didn't guess it yet, until you find copper, your armies will be armed with sticks and stones.
There are a few choice
trade goods that I have added in order to make exotic trade more than mere points in the stats. There are locations all over the map with natural deposits of luxury goods such as dye, silk, spices and tabac/tobacco. These will be discovered as nations grow and horizons expand. Most will give you an eco bonus, perhaps worth several EPs if you trade a lot with other nations. These resources are obviously very rare, and although I will not bar introducing of crops/plants to other areas, the chances of this succeeding is slim to none. It might be a better idea to build plantations to increase the harvest if you only want to increase your revenue.
Of course, this does not limit to stupid plants only. The
fauna on Magnamund is as expected not similar to that of Tellus. The most notable are the Torii, a type of flightless bird similar to OTL
Gastornis/
Diatryma.
These were used by the Ancients as mounts, and although not intellgent like their other servants, they are quick, resilient and docile beasts. For gameplay, the Torii will replace horses, together with...
The
Kage. These are beasts of burden similar to OTL
Protoceratops (images).
Not as big as the Torii, they are more suited as pack animals. Still, they might serve as mounts for smaller species, and their large neck frills can provide cover against weapons and missiles. Where the Torii are suited for light cavalry, the Kage can provide lesser humanoids the advantage they need to go toe-to-toe against larger opponents.
There are of course other animals of importance. One is the
Pesh, a sheep-like animal with eight legs. They are fleshy, and provides wool for clothes, and were introduced to Magnamund by the Ancients for these ideal attributes. They also saw to it that all natural(?) predators were driven extinct so that they could simply let the pesh roam the wilds freely. The lack of predators and supervision meant they survived the troubles after the Ancients left - by sheer numbers. Now, they roam the wilds blissfully, free to be domesticated anew by the slaves.
Much of the seas of Magnamund were until recently barren and devoid of life due to mass extinctions that followed the departure of the Ancients. However, life is slowly beginning to re-establish. One of the species that has weathered the storm particularily well is the
Barc. These thrive in shallow waters, and resemble large jellyfish with a carpace on their upper side. If you picture a tortoise shell with tentacles drifting underneath, that is roughly how a barc looks. They are quite nutricious, and their shells are ideal as large bowls or makeshift helmets.
Lastly, there is one animal worthy of note. The
Zang are huge subterranean "worms" known to travel in packs of twelve to twenty.
(another image)These monsters can grow up to twenty meters long, and five meters high. Little is known about them, as they seldom surface. However, when they do, they often go on rampant eating sprees, charging ahead on their hundred legs - devouring anything from trees to humans to entire housings.
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Apart from this, you are free to write stories about flora and fauna specific to your area. Just use some common sense, and be reasonable. You can't come up with magical fairies or pods filled with flammable gas which you later use as improvised granades.

Hope it was intersesting, and inspirational.