NationStates

For The Natufian Nation, the Uki is a fiat currency with a central bank managing money supply to stabilize the value. The government also tends to run a small budget surplus which helps. We are not a mineral-rich nation and have little mining activity so it is impractical to put the Uki on a gold standard unless we trade for the gold; not an attractive proposition for the government. There has been talk of pegging the Uki to the currency of one of our richer trading partners but this has little serious traction so far.

Basically like American currency- If people have faith that it’s worth something, then it’s worth something. Inflation and deflation still exist, but not because core beliefs change.

The Kamot pound is a fiat currency not backed by any commodity.

The gdyn is a fiat currency and has not been backed by any commodity since our nation left the gold standard in the early 20th century.

The Drongonian Dollar is a fiat currency, not backed by a commodity. Our currency was founded as fiat and has never been representative.

The Crubenat is made with a thin sheet of whatever material it is made of. The faces are actually carved on the Crube, not printed

The Achaean corcino was backed by different standards throughout its history:

1789-1791: Spanish real, gold
1791-1792: Acayanos, gold
1792-1800: Peseta acayana, gold
1800-1829: Nueva peseta acayana (new Achaean peseta), silver
1829-1833: Nueva peseta real acayana, silver and gold
1833-1933: Peso acayano, silver and gold
1933-1935: Peso de transación acayano (Achaean transitional peso), fiat
1935-Present: Corcino, fiat

The Tsenyen is a fiat currency. There have been calls to adopt the gold standard or even to link it to a commodity like oil, but so far such calls have been rejected.

The Chuckian Argentum is a commodity currency that is backed by Gold, Silver, and Platinum.

The Xosar is an atomic credit based system. The amount of currency is tied to the amount of human-accessible matter as measured by hydrogen atom weight units.

.

The Aldish liber is a fiat currency, and has been so ever since the convertibility of libers to sterling silver was suspended indefinitely in 1930. (Yes, this does mean Aldina went straight from the silver standard to fiat money, skipping the gold standard entirely.)

The pound marten is a floating commodity money, based on the average market prices for a number of commodities, including inter alia silver, gold, copper and iron. Control over the supply of currency means that the official target of 0 per cent inflation is mostly achieved. Coins are made of bronze, silver and gold, and bronze and gold coins may be converted into silver coins per their exchange rate. Notes may be redeemed for their value in silver. Despite this, the face value of coins is often up to two times of their quantity of metal, and so it is uneconomical for use as bullion.

gold

The drawing power of our wrestlers.

The newbuck [NB] is part cybercurrency, but physical coins do exist as well, though not extremely common, and produced infrequently.
Because of this, and also being ahead of OOC Earth time, newbucks can be almost-magically exchanged from physical and digital (though it’s more difficult if digital to physical).
(Edit: Would be (new edit: maybe) at least partly private currency if a bit more closer to the canon Slime Rancher universe, but nah.)

(Yes, lucky slimes just so happen to produce newbucks, but you can also delete your own newbucks that are digital (and obviously just throwing physical newbucks into something destructive works too), to combat economic inflation.)

One Glassian Newbuck (GON) is worth 0.36 NSD.
One newcent [NC] is equivalent to 0.01 NB, basically how pennies are to dollars (though not inefficient).

The Lunen is a Fiat Currency, after leaving the Precious Metal Program in 1939, after the start of World War Two.

The Vallois Lire is a a fiat currency with a free floating value since Valloire dropped the gold standard in 1969. However, its value relative other currencies does play a role in setting monetary policy.

The Lillorainian Mark uses a mixed system. While the Gold Standard/RS is a thing to a degree, the value of the Mark is also adjusted to the general populace's trust (usually very high), to the acute need of more or less money in circulation, as well as to the value of other currencies.
The National Bank of Lillorainen is nationalized, to align the monetary policy with the general needs.

The Ouar (literally gold in the Synthesis Celtic Language) is actually backed by quantities of a few precious metals. Gaeilia-Brithon-Iberi operates by market socialism and has strong protections for it's countryside that operates more like distributism, where barter is common over use of the Ouar.

The Aikolandais franc is a fiat currency and has been since our nation officially left the gold standard in 1938.

The Therma is a fiat currency however it is backed by substantial reserves of valuable minerals and trade

The Cepel is a fiat currency that is backed by Westmarch-Eastmarch old currency (Gold, Silver, and other precious metal)

My Reichseuro uses gold and silver too as its commodity.

The full strength of Yohannes’ networks of international trade and investment in over 500 World Assembly member states and countries since 2010.