The list of best altcoins must be started by Ethereum, which is the second most valuable trading currency after Bitcoin. As one of the most popular crypto, you can buy Ethereum in any trading platform.
Yes ethereum is in the top choices that good for investment, but of course you need to invest on different altcoins not only in one crypto. There's a lot of great potential altcoins and also shitcoins that's why you need to analyze carefully on what kind of coin that you will buy.