Honestly, it all depends on what your preferences are. I can get on here and tell you what has worked for me, but I tend to be more aggressive in my investing with altcoins.
Perhaps you are more of a conservative trader. In this case, my advice would be of little value as it would cause you to deviate from your own beliefs or comfort.
That said, one coin that has worked for me as a safer bet that also surprises from time-to-time is ENJ (Enjin coin).
I have had a great experience tracking and trading ENJ, so this might be a good place for you to look next if you haven't already.