The best choice is bitcoin and bitcoin cash for me now. But if you are interested in other coins, then only you should make a choice. This is your money and your risks.
The main thing, remember, you do not need to buy a coin when it reached the peak value. Wait until the coin becomes the cheapest one in the last time and invest only after that. In the case of large projects, it is also very important to follow the news about the development companies. It should be remembered that in the market any events can affect the course.

Also, you should not forget the basic rules of safe investment. Try not to invest the last money that you can not afford to lose. It is not recommended to invest the entire amount in one currency, because this increases the risk of losing funds. Fill your investment portfolio with a large number of currencies to protect yourself and increase your potential income.
I wish you good luck!