Collect aluminum cans. 46 cents per pound. https://iscrapapp.com/prices/
Donate plasma at a blood bank near you. https://www.donatingplasma.org/donation/find-a-donor-center
Hold a yard / garage sale.
Use a credit card with generous cash back rewards. My PayPal card gives me 2-3%..
Own stocks that pay monthly dividends. https://cheapogroovo.typepad.com/blog/2022/12/december-2022-investment-update-one-new-addition.html