Alt coins refer to alternative cryptocurrencies that are not as well-known as Bitcoin, Ethereum, or other popular cryptocurrencies. There are many alt coins, each with their own unique features, uses, and communities. Some examples of alt coins include:

1. Litecoin (LTC)

2. Dogecoin (DOGE)

3. Cardano (ADA)

4. Polkadot (DOT)

5. Solana (SOL)

6. Stellar (XLM)

7. Chainlink (LINK)

8. Bitcoin Cash (BCH)

9. EOS

10. Monero (XMR)

Keep in mind that the alt coin landscape is constantly evolving, and new coins are emerging all the time. If you're interested in learning more about a specific alt coin, feel free to ask!