Bitcoin is the "safest" crypto. Probably the closest comp to buying an ETF in the crypto space.
Ethereum is the clear #2. Most developed smart contract platform with the biggest network. Probably equivalent to buying a large cap stock.
Then there are a handful of altcoins that are solid projects (many with technical superiority to BTC and ETH) but don't have the adoption yet and aren't as much of a sure thing. Cardano, Solana, Polkadot, Algorand, Avalanche, Chainlink, Polygon, Cosmos come to mind. They would be the equivalent of growth stocks.
And then of course you have the meme coins... Dogecoin, Shiba Inu, and the like. Those are the penny stocks of crypto.
If you want to dip your toes into the space, it's not a bad idea to start with Bitcoin and then branch out as you research more.