Hard noise reduction dampers for nema 17 motors. Usefull for no place to set huge dampers. This one is only 1 mm.
For more noise reduction better set dampers from two sides of motor bracket to prevent vibration trasmission through bolts.
ABS maker PETG, TPU, Flex
You can vary infill and walls on your own. More hollow, more reduction. Better use flexy materials. PETG is almost works.