I use a number of centering and grounding exercises in workshops.
Here are the main three:
Three Centres exercise
https://wayofnaturalbeing.co.uk/wp-content/uploads/2017/11/Centering-Exercise-new-clean2.mp3
Breathing Sphere exercise
https://wayofnaturalbeing.co.uk/wp-content/uploads/2021/06/Breathing-Sphere-Exercise.m4a
Spiral Breathing exercise
https://wayofnaturalbeing.co.uk/wp-content/uploads/2021/06/Spiral-Breathing-Exercise.m4a