Hmmmm... The only things I can think of are:

• Posts and Comments about topics are willing to upvote you for.
• Run a witness node, but you won't earn money unless you're in Top 20, I think.
• Run a Proof-of-Access node on 3Speak. Last time I heard they were doing beta-testing for this, I don't know if you can still earn money from that.
• Open a Subscription on INLEO, you'll need a Premium Account for that, and you'll also need to find people willing to pay you for the content you provide.