Apart from bitcoin, there are a few good altcoins such as Ethereum, Neo, Litecoin, Bitcoin cash, and Cardano.
I prefer for bitcoin because I know it has a big exchange enormous profit due to the fluctuations on prices, the other coins was based on bitcoin prices so better to have some bitcoin .I know for now its too much risky to invest some money but as my study its much better to have another coin so that it has a choices and to determine those who has potentials.