The top 10 foreign currencies most traded globally this year (2021) are:

1. United States Dollar (USD)
2. Euro (EUR)
3. Japanese Yen (JPY)
4. British Pound Sterling (GBP)
5. Australian Dollar (AUD)
6. Canadian Dollar (CAD)
7. Swiss Franc (CHF)
8. Chinese Yuan (CNY)
9. New Zealand Dollar (NZD)
10. Mexican Peso (MXN)

Please note that currency rankings can vary slightly depending on the source and time period considered.