By putting certain things underneath your pillow, you will allow those metaphysical properties to interact with your dreams, and your person all throughout the night, when you sleep upon that pillow. Here is a small list of constructs you can put underneath your pillow, that will provide to you certain energies, minds states, and physical stimulus throughout the night based on what they are:

• Lapis lazuli under your pillow for awareness of your dreams, and vividness of those dreams.
• Clear quartz under your pillow to wake up with more energy, after you awake from your sleep.
• Bayleaf under your pillow in order to have more prophetic dreams.
• Chamomile under your pillow in order to promote relaxation, and good  dreams.
• Rose petals under your pillow in order to bring love into your waking life.
• Peppermint under your pillow in order to promote relaxation, and vivid dreams.
• Lavender under your pillow in order to promote calm, and in order for you to sleep well.
• Anise under your pillow in order to prevent nightmares.
• Rosemary under your pillow in order to prevent nightmares, and to bring deep sleep.
• Garlic under your pillow in order to promote sleep well.
• You can put a blade of grass, or a leaf underneath your pillow to promote growth, and change in your waking life.
• Money under your pillow for wealth, and prosperity in your waking life.
• You can put a picture of someone underneath your pillow in order to connect with them better.
• You can put the name of someone underneath your pillow in order to connect with them better.
• You can put all manner of sigil underneath your pillow in order to get the effect of that Sigil into your dreams, and waking life.