Just print; design it yourseslf; scan...all of the above are possible.
The easiest thing to do is to go to Thingiverse and scan thousands of mostly free designs. Download one and print it in the size you want, with the filament that you want. That is what I did with the Thinker models.
Or, you can get any of many CAD programs, some free, some very costly, and learn how to design and produce an object. That is what I did with the fishing lure I put up here today.
Lastly, you can take 50 or 100 pictures of any object, and feed them into a program (Meshroom) is one of many. That program is supposed to make the model for you. I input 43 pix into it today. I have no idea how to get the model file out of it yet.
Off to the learning room, again...for this old codger.