Like You Said, Apart From Airdrops And Bounties What Other Ways Can One Make Money Via Cryptocurrency But Below Ideas Requires Investing Funds ( Capital )

You Can Actually Make Money Via Masternodes ( Proof Of Stakes Coins )

You Can Visit This Link https://steemit.com/cryptocurrency/@michellerhey/how-to-make-money-with-cryptocurrency-proof-of-stake-coins  Also Visit ( https://masternode.fans/ Or https://masternodes.pro/statistics )

To Learn More About Masternodes

Conclusion:

Just Make Good And Cool Research For Yourself And Decide On Which POS ( Proof Of Stake Coin )You Will Invest In.