No one has the correct answer to this question, because cryptocurrencies have different characteristics and serve different purposes. Thats is why people follow different coins based on their preferences and convictions. Some big cryptocurrencies (e.g. BTC, ETH, LTC, XRP, XMR, DASH, etc.) are among them, however there is a bunch of other coins that are also very perspective. And no one knows which is the best one out of them 