I would think those are precisely the ones that have gone up quite a bit already.  I'm pretty sure there are more "diamonds in the rough" that still have potential to increase significantly.  Having said that, I couldn't say with a straight face what they are.  I've been placing my bets on NEO and PIVX, but I'm not recommending those to anyone as a tip.  They're just coins I like which earn income, and if their prices go up, all the better.

But yeah, the safe ones would probably be what you see first on Coinmarketcap.  Then again, there's nothing guaranteed or totally safe in crypto.  Anything can happen, and it's not even certain that any coin will "moon".  The whole market could come tumbling down tomorrow.