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 have a buckwheat pillow. I find it extremely comfortable, it reduced my neck pain. It is hard, but molds to the shape of your neck in a very comfortable way. It doesnt get lumoy in the same way a traditional pillow does.I have replaced it once now, first set lasted about 2 years. I personally greatly value that it is renewable material. The up front is kinda high, but the cost to replace the stuffing is low. I think it'll be comparable to a cheap regular pillow after one more replacement, which I think it's definitely durable enough to get to I also bet im paying a but more for hulls than i needed if i was willing to shop around. It's also cool cause you can clean the pillow itself quite easily by just emptying the hulls out. It stays cooler than a standard pillow.
For downsides, it is like sleeping on a beanbag. I've heard some say it's "loud" in that your ear is pressed right up against it and you can hear the hulls(?) Move around if you move, nit a problem for me, but people with sensory issues beware. I found that the grain made a texture that overtime annoyed my cheek, but a second pillow case was enough to fix that problem for me. It's quite heavy, I like this because it neans it moves less, but my wife finds it annoying.
I got one, had my wife get one after trying mine and I'm thinking of a gettibg a 3rd at some point. I got mine from comfy comfy and I would recommend their contour version as it seems to keep the hulls distributed more evenly than the standard.