These are the methods you can use to earn free cryptocurrency
Eg :
1. AMA(Ask me anything)
2. Testnet
3. Play to earn games
4. Bounty
5. Ambassador Programs
Some P2E games today requires an investment so I don’t want to include this on way to earn free crypto. You can also add the signature campaign here and also other promotional campaign like a contest here in the forum and the common here is the airdrop.