Here's a collection on some very basic shapes intended to help some users tune their machines. It's easy to make these for yourself just by taking the basic cube and non-uniformly scaling it in your slicer, but not everyone is sure how to do that so I'm providing these models as a basic aid.

Basic Use Suggestions:

1. Pick a tester to check your printer's settings and physical setup work across your print bed. The 0.2mm tester is a good option.
2. Check your layer height in your slicer, set it to 0.2mm if not already there
3. Print and check, if you have issues, you can consider adjusting things like: print temperature, nozzle z-offset, running calibration before every print, print speed, line width, etc. Note during the print, you can change at least the nozzle temp to see the effect on the print. Note that if you have levelling issues, then first you want to see a fairly uniform print fully completed before following-up with another print where you adjust the temperature mid-print.
4. You may want to try printing with the thicker versions to see the effect, just consider adjusting your layer thickness setting to match unless you are intentionally checking multilayer quality.

The 1.2mm model is intended to be used to tune ironing settings (such as are available in OrcaSlicer).