I recently purchased the Prusa i3 MK3S+ 3D printer kit. The kit was delivered by FedEx within a week and I began the assembly process being rewarded with gummy bears along the way (there are several documented steps in the assembly of the printer that involve gummy bears).
My first serious creation was a replica of some mini-shelves which taught me quite a lot about SketchUp (which is not really considered “serious” CAD software).
The first creation of any practical value was a clip to secure the custom built drawers in the back of a vehicle. Being custom built drawers, the design isn’t particularly useful to anyone else, but it feels good to be able to develop custom solutions to unique problems, even if the invention won’t make me rich!
The most recent discovery is of programmable 3D design – or parametric design. This uses code to make easily customisable components. The example that I’ve been fiddling with is luggage tags which emboss custom text and resize to fit the text as required. Still not earth-shattering, but fun to play with the code, nonetheless!