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?
I can't deny that all of them are good to hold in the long term also they are all good to do day trade as well.
But honestly none of them is giving me a profit, instead, some of the altcoins is the one who gave me a good profit,
though they are just in the middle of class of the altcoins in the market that has a quite good in terms of volume.