We usually use Brain Breaks 3 times a day in school to support children in self-regulation and calming. It's a guided relaxation/breathing exercise the children really enjoy. Use the video from the link above to allow your child to have their own Brain Break whenever they need - or at set points in the day as we do in school.
You can find lots of really lovely activities and stories to support emotional resilience on this website from ELSA: https://www.elsa-support.co.uk/category/free-resources/
MindUp have a page of suggested activities which you can find here
. These promote mindfulness and self-awareness.
You can find some really useful guidance and activities to support calmness here
on the Calm Zone page.
Keeping a journal can be really helpful in promoting mindfulness and a feeling of emotional wellness. You can download some useful journal pages from the pack below.