There are thousands of altcoins in the crypto currency market, but it is not possible to invest in all altcoins, and even if it is possible, holding those altcoins for a long time is very risky, especially other altcoins except the top favorite altcoins of the coin market can be down from the market at any time. This is why all altcoins are recommended to invest in.
However, I have kept the following altcoins as one of my favorite altcoins in my portfolio.
Ethereum
Litecoin
Bitcoin cash
Monero
Neo
Near Protocol
Polkadot
Solana
Binance Coin