There are many different fills for your pillow. Some people prefer a cushy or poofy pillow and down is their favorite.
Down is the most popular filler and it helps that they make one for every sleeper – stomach, back, or side.
Cotton pillows tend to be firmer & less squashy than down.
Foam pillows - latex & memory foam are best for those who sleep on their side or back. Latex foam comes from rubber trees and memory foam is a synthetic material.
Natural latex pillows offer incredible support, with a little bit of give. Because it’s a porous material, latex has some spring do it (as opposed to memory foam, which is very dense & adjusts immediately to your head - with very little bounce).
Memory foam conforms to your shape.