Great Compassion Mantra is one of the Buddhist mantra that people recite. It's also called as Maha Karuna Dharani (大悲咒）. Some people recite it up to 108 every day. I also know a friend whose daily main practice is the Great Compassion Mantra recitation. In this mantra we actually recite the 84 manifestation of Avalokiteshvara Bodhisatva Mahasatva (Guan Yin Pu Sa). May all beings be free from all sufferings. Amitabha...
Here's a Youtube video on Great Compassion Mantra.