There are too many altcoins and crypto projects. But you have to find and select a project with good team and good project. I am holding some different altcoins but all of them are popular. I believe that one should never put all eggs in one basket.I am holding Ethereum, Litecoin, Ripple, ADA. I invested in Ethereum because of popularity of smart contracts and decentralized applications. Many Erc20 tokens are created and some of them can be useful. This gives more popularity and success to ethereum. I invested in Ripple when it was regularly making news for tremendous rise in price. But now most of my investment in Ripple is down. I invested in Litecoin very earlier.