If you are the type that likes gambling, then I will advise you go for ripple also because ripple to me is a coin of luck and there is no assurance that they will rise without the bull run and even with bull run, the chances of them rising more than what they are now is very low, so I will advise you still buy more of those two coins your mentioned (BTC and ETH) which are still the most popular and reliable coins for now. Instead of ripple as third choice of investment, why not buy coins like binance coin, this is another coin that I am sure of its full development and will be very useful for both investment and as utility coin.