Regional coin

From SMO.wiki

Regional coins, also known as purple coins, are one of the main collectibles in the game. Most kingdoms have regional coins, with the exceptions being Cloud Kingdom, Ruined Kingdom, Dark Side, and Darker Side. They can be found in each kingdom's overworld, as well as some sub-worlds. Each kingdom's regional coins are a different shape. Regional coins can be used to purchase outfits and souvenirs. Each kingdom's regional coins are shaped differently and can only be used in the kingdom in which they were found. Some kingdoms, typically the smaller ones, have 50 regional coins, and others, typically larger, have 100.

Kingdom Regional coins
Cap Kingdom 50
Cascade Kingdom 50
Sand Kingdom 100
Lake Kingdom 50
Wooded Kingdom 100
Cloud Kingdom None
Lost Kingdom 50
Metro Kingdom 100
Snow Kingdom 50
Seaside Kingdom 100
Luncheon Kingdom 100
Ruined Kingdom None
Bowser's Kingdom 100
Moon Kingdom 50
Mushroom Kingdom 100
Dark Side None
Darker Side None