There are several ways you can earn free cryptocurrency:

Airdrops: Some cryptocurrency projects will give away free tokens or coins to promote their project. To qualify for an airdrop, you may need to hold a certain amount of a specific cryptocurrency, follow the project's social media accounts, or complete other tasks. Airdrops can be a good way to earn free cryptocurrency, but it's important to be cautious and do your own research before participating in any airdrop. Here are a few notable crypto airdrops:

1. Stellar Lumens (XLM): In 2017, the Stellar Development Foundation distributed 16 billion XLM (worth approximately $16 million at the time) to Bitcoin and Ripple holders.

2. TRON (TRX): In 2018, TRON held an airdrop for Ethereum holders, distributing 30 million TRX (worth approximately $1.7 million at the time) to participating Ethereum holders.

3. EOS: EOS held an airdrop for Ethereum holders in 2018, distributing EOS tokens to participating Ethereum holders.

4. Ontology (ONT): In 2018, Ontology held an airdrop for NEO holders, distributing ONT tokens to participating NEO holders.

5. Cardano (ADA): In 2020, Cardano held an airdrop for Ethereum and Binance Smart Chain (BSC) holders, distributing ADA to participating holders.

Faucets: Some websites or apps will give away small amounts of cryptocurrency for free as a way to introduce people to the concept. These amounts are usually very small, but it's a simple way to get started with cryptocurrency. While there are many crypto faucets available, it's important to be cautious and do your own research before using any of them, as some may be scams or may not be trustworthy. Here are a few crypto faucets that have been around for a while and have a good reputation:

1. FreeBitco.in: This is a Bitcoin faucet that allows users to earn small amounts of BTC by completing tasks like solving captchas or playing games.

2. Cointiply: This is a Bitcoin and Dogecoin faucet that allows users to earn small amounts of these cryptocurrencies by completing tasks like taking surveys, watching videos, and visiting websites.

3. Moon Bitcoin: This is a Bitcoin faucet that allows users to earn small amounts of BTC by completing tasks like solving captchas or playing games.

4. Moon Dogecoin: This is a Dogecoin faucet that allows users to earn small amounts of DOGE by completing tasks like solving captchas or playing games.

Completing tasks: Some websites and apps will pay you small amounts of cryptocurrency for completing tasks like taking surveys, testing apps, or watching videos.

Offer services in exchange for cryptocurrency: If you have a skill or service that you can offer, you may be able to find someone who is willing to pay you in cryptocurrency for your work.

Participate in cryptocurrency giveaways: Some cryptocurrency users and communities will hold giveaways of free coins or tokens on social media or other online platforms.

It's important to keep in mind that earning free cryptocurrency may not always be easy, and it may require some effort on your part. Additionally, it bears repeating that it is important to do your own research and be cautious of any offers that seem too good to be true, as they may be scams.