I'm a civil engineer and surveyor, so it's lots of reading, writing, calculations, mapping, and working with computer software (AutoCAD, HY-8, HEC-RAS, TR-55, HydroCAD, Hyrdaflow). It's pretty boring, but the money is good and it allowed me to pay off my house in 5.5 years.
Thankfully, I own a 9-acre farm where I have a greenhouse, chicken house, several large gardens, fruit tree orchard, fish ponds, woods, etc. I sell fruits, vegetables, and several hundred dozen eggs per year to neighbors, friends, family, and co-workers.
I also have a 3-car garage where I take a few jobs per month working on people's cars and "flipping" cars that I buy for a couple hundred dollars and fix up for profit. I recently started to buy cheap (broken) riding/push lawnmowers and fix them up for sale. These projects doesn't always work out in my favor, haha.
I'm good friends with a realtor who sets me up with jobs removing "junk" from houses that he is staging for sale. Some of the best tools, hardware, and building materials I have came from doing this. I get paid to remove the "junk," but also make a profit from "scrapping" metal and selling certain items that I find.
It goes without saying that I'm also an avid "dumpster diver." Because of my job, I have access to many construction sites and I've climbed into numerous dumpsters whilst wearing a suit and tie, haha. People are so wasteful and the great stuff that I find never ceases to amaze me.