My favorite is called the D-Core Pillow:

What makes it my all-time favorite pillow?

The D-Core pillow supports my neck no matter how I’m sleeping. I tend to roll side to side while I sleep, aka. tossing and turning. I usually start by laying on my back. As a result, if I’m using a regular pillow, my chin is close to touching my chest. But with the D-Core pillow, my head is nestled down into the pillow, and my neck is supported by the pillow. Then when I need to roll to my side, the side panels are thick enough to maintain my cervical line. This means that my spine stays parallel to the bed, and my neck doesn’t get a pinch. Excellent sleep achieved!

The D-Core® Cervical Support Pillow helps relieve tension, headaches, and neck spasms by providing proper alignment of the neck while sleeping and is commonly used to help treat a variety of conditions affecting the neck and shoulders.

For back sleeping, a very firm cervical roll supports the neck while the D-shaped center gently cradles the head for better sleep. For side sleeping, the raised side panels help keep the head level for proper alignment of the spine.

In order to provide therapeutic benefits and help restore the natural curve of the neck, two very firm cervical rolls provide different support options. Use the smaller neck roll if you are in the adjustment phase or if you prefer slightly less support; use the larger neck roll for maximum support.

It may take some time to adjust to this cervical pillow and immediate overuse may actually increase neck pain. For best results, slowly ease into orthopedic correction by alternating between this pillow and your current pillow.

The D-Core pillow fits in a standard pillow case.