There is no such thing as best pair that can be applied to all traders. It depends on your strategy, your account size, and many other factors. For example if you want to trade based on a scalping strategy, you need small spread and smooth price movements, EURUSD might be a good choice. If you really want a flat market to try consolidation strategies you may be interested in EURCHF or EURGBP. Some people like fast price movements because they can earn fast (and lose fast), for these people GBPJPY or GBPUSD are good choices. But some pairs like EURUSD, USDJPY are mostly good for many different strategy types, they also have very high liquidity so they’re recommended.
1