If you have some capital you could try your hand at trading. Trading can be lucrative if you are extracting alpha from upcoming events, shorting mainnet launches, and using trading robots.
Unidex Bot, Has Bot, 3Commas are the best trading robots and they all are capable of daily returns of at least 5%. You may have heard of liquidity mining; it's a new way to mine coins. Normally you hold 1:1 ratio on a Decentralized Exchange like Uniswap, Bancor, or Balancer, Curve etc. For example Ampleforth provides a 85% a year ROI with a 3x bonus after staking for 30 days. You can mine coins by providing liquidity of a coin to farm another coin. Another example is UNDB is air dropping UNDB to holders and liquidity providers that have over .5 UNDB. If you understand a lot about technology you could build ethereum miners with spare parts on Ebay and resell them. Hardware miners can make a lot of money when they are using solar power. The biggest way they make thier money is from buying spare parts and making mining rigs. All of these positions vary depending on how much time and capital is invested.