Mindfulness is a powerful and effective skill to develop metacognitive awareness. It also functions as a form of exposure, as individuals are to nonjudgmentally observe their uncomfortable and distressing thoughts and feelings. This process reduces experiential avoidance and increases distress tolerance. Below are resources related to mindfulness that may help you and/or your clients.
Resources from Dr. Jon Kabat-Zinn
Breathscape Guided Mindfulness Meditation (20 minutes)
Resources from Dr. Christopher Germer
Resources from NewMindfulLife