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.
I switched to buckwheat pillows a few years ago and I've been a fan. It's a really interesting texture that you can move and shape really easily, but then when you apply pressure to it, it firms up and holds its shape. So, you get a really supportive pillow that's molded to your head and neck (For reference, I'm a side sleeper). The only downside I've noticed is the filling degrades relatively quickly, and after about a year it loses a lot of its volume and doesn't hold its shape as well, so you'll need to replace it. The bright side is that it's fairly cheap, and entirely biodegradable.
Mine is ~10 years old now and still holding up fine for me. I replaced a travel size one with a queen size, the smaller one definitely degraded but I was rougher on pillows back then.
There's a story here, I just know it.
I remember once looking over my sister's shoulder while she was on MSN messenger and a mutual friend chose that moment to confess (via MSN messenger) that he fucked pillows for practice.