Do you mean other cryptocurrencies besides Bitcoin? Well, here are a few of the most important ones:

1) Litecoin (LTC)
2) Ethereum (ETH)
3) Zcash (ZEC)
4) Dash
5) Ripple (XRP)
6) Monero (XMR)

This websites provides you more information about each of them: https://www.investopedia.com/tech/6-most-important-cryptocurrencies-other-bitcoin/