Hi Jeff. I just wanted to invite you to contribute (when you feel like it) to this thread:
https://permies.com/t/102321/Small-homemade-gadgets It's all about gadgets we make, whether humble or ingenious, using whatever materials made sense or we happened to have on-hand.
Its a place where a number of us have posted pictures & stories or descriptions. The gadgets posted have been quite varied, and the one key idea is their usefulness for making our homestead/permies/self-reliant lives easier or more convenient. Of course, no reason why they couldn't be something one turns out for sale as part of cash income needed.