My favourite pairs are GBP/USD, EUR/USD, USD/JPY, AUD/USD and USD/CAD. I also trade Brent Crude and Gold sometimes on MT4. I trade USDCAD and Crude the most, because Oil has a negative correlation with USD/CAD of about 93% between 2000 through 2016.
When oil goes up, USD/CAD goes down. When oil goes down, USD/CAD goes up. Happy Trading Folks. 😎