I don't think there is a coin that make easy 3x right now. They will make 3x in lnog term, or at least in 9-12 months period but there is no "easy" way to do it. Patience is the key for serious investment. If you play with big money you know that by now already.
Yeah right, nothing will be easy to make 3x in the near future. You can see the trading volume on in coinmarketcap, by looking at the volume you can choose the exact coin to hold. Because I personally believe if the altcoin that has the potential will easily increase at least will be faster when compared with altcoins who have low interesting.