Almost all world currencies take part in Forex trading, however, the volume of transactions for most of them does not exceed 1%.
The main currency pairs in Forex are:
USD/JPY (dollar/Japanese yen);
USD/CHF (dollar/Swiss franc);
GBP/USD (British pound/dollar).
More than 80% of transactions in the foreign exchange market are made on these pairs and other combinations of currencies included in these pairs.
Also quite popular are currency pairs with the participation of commodity currencies, the exchange rate of which depends on the prices of minerals:
USD/CAD (dollar/Canadian dollar);
AUD/USD (Australian dollar/dollar);
NZD/USD (New Zealand dollar/dollar).