In many ways the Equestrian Bit is considered the world standard, and many other countries (specifically those with large pony populations) use it as their official currency.
The Bit is a thick, heavy Golden coin, with an equally heavy Silver denomination.
Bits do not come in Copper, nor Platinum, however, their sheer heft means that they are valued at twice the worth of the equivalent Welaren coin. (Welaren Value 2x)
Welarens are unusual amongst primarily pony states, in that they mint their own currency, and are damn proud of the fact. The only other pony nation, in the current era, to do so is Unicornia.
The Welaren Crown is a slightly oblong coin, with a square whole in the center. It is common for Welarens to loop string or chains through these holes in lieu of carrying their coins in a pouch.
Welaren coins come in Platinum, Gold, Silver, and Copper, but all of them are composed primarily of silver, except for copper, which is indeed pure copper.
Gryphons actually mint more than one form of currency, however the term Ducat refers specifically to the golden coins, while Fiat refers to a sort of ceramic disc that Gryphons carry while abroad.
The Ducat is a wide, but extremely thin and soft golden coin, with a very small hole in the center. Along the coin's edges are notches.
The Ducat is meant to be cut into pieces, and as such, no silver, or copper variations of this coin exist. A whole complete Gryphon Ducat is worth roughly half the value of a Welaren Crown (Welaren Value 1/2)
The Fiat is a thin, but sturdy ceramic disc that has no value of its own, but is often traded amongst Gryphons outside of their territory, as if it were gold. Fiats can then be exchanged for Ducats upon return home.
A Fiat is considered to be roughly the value of 20 Ducats, and can be broken as needed, in much the same fashion as a Ducat.
Fiats are not considered currency in most of the world, as the Gryphon empire does not recognise non-Gryphons as persons, and thus will not exchange Fiats for Ducats to them.
In an odd quirk, Zebra always shared nearly identical currencies with the Abyssinian people, such to the point that both nations now use the same shared currency.
The Zebran Birr is a bronze coin, of varying sizes, depending on its worth. The standard Birr has about the same weight and heft of a Golden Equestrian Bit, but with rounded soft edges, giving it the appearance of a pebble made of bronze.
As Birrs are only made of copper, they don't tend to be valued very highly. They are worth about the same amount as a Welaren Copper piece, with lesser denominations having exceedingly lower value. (Welaren Value 1% or lower)
The ponies of Unicornia never stopped using their ancient currency, in their isolation.
The Unicornian Drachma is a heavy golden coin with a heavily ridged edge, and an intricate relief in three dimensions. Unlike other currencies, the Unicornian Drachma also acts as a magical sponge or battery of sorts, capable of holding and releasing small amounts of magic (up to 1st level spells).
Other nations will not trade actively in Unicornian Drachmas, and Unicornia refuses to trade in any other form of currency. Officially speaking, Unicornian Drachmas have no value as coins, but... because of their rarity, and their unusual properties, they have been known to sell for very high amounts to collectors and spellcasters, alike. (Welaren Value either 0 or 100x + )
A Note on Dragon's Hordes - Dragons in their own nation have no currency of their own, and mint no currency, instead, they regularly actively trade valuable gemstones with other nations, specifically to acquire precious metals for their hordes
