Pokémon (Series)

Main Series
These are coins that are found in the main series RPG Pokémon games.

Game Corner
Every Pokémon game prior to Generation 5 contains a Game Corner, and each of these Game Corners has a coin system where you can buy and gamble with coins. While we never get to see what these coins look like on their own, we can observe the Coin Case to get an idea.

Pay Day
Introduced in Generation 1, the move Pay Day has the Pokémon throw a coin at the opponent, and after the battle you receive money. The higher the level of the Pokémon using Pay Day, the more money you get. The coin that is thrown resembles a koban, a type of coin used in Japan from 1601 to 1867.

Amulet Coin
The Amulet Coin is a held item that will double the money received after a battle if the holder of the item takes part in the battle. It also doubles the money received by the move Pay Day or G-Max Gold Rush if they were used during the battle. Only one Amulet Coin can be obtained in each game without trading, with the exception of Pokémon Sword and Shield, where the Cram-o-matic in the Isle of Armor can produce an infinite amount of them.

Wealthy Coin
The Wealthy Coin is an accessory in Pokémon Diamond, Pearl and Platinum. It can be applied to a Pokémon in the dress up mode. It can be obtained randomly from the Massage Girl in Veilstone City when she massages one of your Pokémon, however this can only be done once a day.

Relic Items
In Generation 5, there are several Relic items that can be found in the Abyssal Ruins. Three of these items are coins. The only purpose of the Relic items is to be sold to a Billionaire in Undella Town for a large amount of money.

Pokémon Mystery Dungeon
These are coins found in the Pokémon Mystery Dungeon series.

Poké
The main currency of the Pokémon Mystery Dungeon series is Poké. It can be found in dungeons, by doing missions, or by selling items. Similar to the main series, if the move Pay Day is used to knock out an opponent, they will drop some Poké in addition to whatever item they were holding. Depending on the game, when you are knocked out in a dungeon you will either lose none, half, or all of your Poké. In Pokémon Mystery Dungeon: Gates to Infinity, there is a dungeon named after Poké called Poké Forest. As you can expect, there is a massive amount of Poké to be found there.

Dream Coin
In Pokémon Mystery Dungeon: Explorers of Sky, there is at least one exclusive item for each Pokémon that gives that Pokémon or any other Pokémon in its evolution line a unique buff. Hypno's exclusive item is the Dream Coin. If it is in the bag, any Dark-type attacks used on Drowzee or Hypno will heal them instead of damaging them. The Dream Coin can be obtained by trading in 5 different exclusive items at the Croagunk Swap Shop.

Trivia

 * Porygon is the most expensive Pokémon that is able to be purchased at any game corner, at a whopping 9999(!) coins.
 * The Wealthy Coin accessory has a total of 15 coins in its sprite artwork. Why it is called Wealthy Coin instead of Wealthy Coins is unknown.