It's hard to say which one is the best. But you can refer: BTC, NEO, ETH
Today it is difficult to get any profits. If you hold coins for a long time, better stop at Ethereum and NEO. Just my choice.
Ethereum and neo are good crypto currencies but one must include bitcoin, the mother of all crypto currencies in his collection of digital assets. What an investor can earn through bitcoin cannot be even imagined by the help of any altcoins. No matter how good is Ethereum, still it is too below bitcoin.Diversification is good but neglecting bitcoin would become a regret after the time passes by. I have seen many such cases.