3D design
If you can visualise something in your head and draw it in CAD software, you can contract yourself out to many technical businesses.

Software: Inventor or Fusion 360
Service: Design steel structures, pipework, carports, tables or whatever else clients want. Create a technical drawing to present to the client. Get approval on the design and let them build it, build it yourself if you have the skills, or outsource the work.
Income: Earn per design or on an hourly rate basis depending on complexity.

A carport design I made for a client.
