I would buy Ethereum (ETH), Litecoin (LTC), Ripple (XRP), and Lisk (LSK). I missed all of them when they were very cheap. And I missed them once more when they were moderately cheap. And now, they have already grown so expensive that x5, though still possible, is almost already wishful thinking. Another thing that I would have done is to continue HODLing them despite the pumps. I did not know, for example, that ETH could go as high as $1,000 and even beyond.