3 model

Free

Metric Holes 1mm-20mm in 1mm steps x 20mm tall

Thingiverse

Free

Calibration box to fine tune Default Extrusion Width, X/Y/Z/E Steps, and Flow Rate

Thingiverse

Free

Lithophane Tester - 100mm diameter, 6mm thick, 60 x 0.1mm steps

Thingiverse