I recommend this video by CNC Kitchen, as it shows an interesting, accurate and detailed, side-by-side comparison of heat deformation of custom 3D printed test samples, printed from various materials:

 - PLA
 - PETG
 - ABS
 - HT-PLA
 - 3dkTOP

He even CNCs a custom, yet simple, test rig in order to carry out the test.

Well worth a watch.

https://www.youtube.com/watch?v=vLrISrkg46g