The picture I linked is of a buckwheat pillow. Had no idea they were a thing before today.
What about silk or bamboo pillow cases?
I’ve only ever really used cotton pillow cases and cotton stuffed pillows. I recently upgraded to a foam pillow that I’m enjoying.
Maybe ceramic pellets could work as well surly it would help both sides of the pillow be cold.
That reminds me of the cheap weighted blanket reviews I saw where people were complaining about them leaking beads after a while. I think it was glass then though.