The following resources provide useful exercises and activities for helping our students (and us) relieve anxiety and stress. Many of them can work as well online/remotely as they do in person.
Mindfulness and Meditation on Campus
22 Mindfulness Exercises, Techniques and Activities for Adults
Mindfulness in the Classroom
Mindfulness in the Classroom: Exercises for Your Students to Focus on Class Content
This material is rather basic, but it could serve as an introduction for students to these concepts.