Short answer is a orthopaedic pillow. They are designed to induce a lordotic curve back into the cervical vertebra. They also keep there form for two years meaning the pillow you go to sleep on in jan ins the pillow you wake up on in dec.
Most people take some time to adjust to the pillows 2-3 weeks and some take to them straight away.
Most are the same memory foam material and should have either a curve or a bump to support neck.
They should be used on there own and a good company will do diffrent thicknessess (large shoulders or petite ladies) low line or normal. We use a company called Harley in UK