For me, that had to be Ripple. I traded for 100%+ thrice and still holding a position at $0.40.
My next coins are:
1) Ripple
2) ADA
3) Bitcoin
4) Ethereum
What's yours?
For me was decred, but earlier 2016 when I received free airdropped tokens. It was 512 free tokens.But it that moment price was about 2 dollars and that all was good free money. That was my great profit. Now price is very high but I don't have any tokens,pity ...